Bump version numbers for beta release.

Backport: Tap viewfinder to restart auto focus

See merge request akwizgran/briar!701

.gitlab-ci.yml

@@ -6,9 +6,18 @@ cache:
     - .gradle/caches
 
 before_script:
+  - set -e
   - export GRADLE_USER_HOME=$PWD/.gradle
-#  - export ANDROID_COMPILE_SDK=`sed -n 's,.*compileSdkVersion\s*\([0-9][0-9]*\).*,\1,p' app/build.gradle`
+  # Accept the license for the Android build tools
-#  - echo y | android --silent update sdk --no-ui --filter android-${ANDROID_COMPILE_SDK}
+  - echo y | /opt/android-sdk/tools/bin/sdkmanager "build-tools;26.0.2"
+  # Download OpenJDK 6 so we can compile against its standard library
+  - JDK_FILE=openjdk-6-jre-headless_6b38-1.13.10-1~deb7u1_amd64.deb
+  - if [ ! -d openjdk ]
+  - then
+  - wget -q http://ftp.uk.debian.org/debian/pool/main/o/openjdk-6/$JDK_FILE
+  - dpkg-deb -x $JDK_FILE openjdk
+  - fi
+  - export JAVA_6_HOME=$PWD/openjdk/usr/lib/jvm/java-6-openjdk-amd64
 
 test:
   script:

bramble-android/build.gradle

@@ -6,99 +6,90 @@ apply plugin: 'witness'
 apply plugin: 'de.undercouch.download'
 
 android {
-	compileSdkVersion 23
+	compileSdkVersion 27
-	buildToolsVersion "23.0.3"
+	buildToolsVersion '26.0.2'
 
 	defaultConfig {
 		minSdkVersion 14
-		targetSdkVersion 22
+		targetSdkVersion 26
-		versionCode 1610
+		versionCode 1618
-		versionName "0.16.10"
+		versionName "0.16.18"
 		consumerProguardFiles 'proguard-rules.txt'
 	}
 
 	compileOptions {
-		sourceCompatibility JavaVersion.VERSION_1_7
+		sourceCompatibility JavaVersion.VERSION_1_8
-		targetCompatibility JavaVersion.VERSION_1_7
+		targetCompatibility JavaVersion.VERSION_1_8
 	}
 }
 
 dependencies {
-	compile project(':bramble-core')
+	implementation project(path: ':bramble-core', configuration: 'default')
-	compile fileTree(dir: 'libs', include: '*.jar')
+	implementation fileTree(dir: 'libs', include: '*.jar')
-	provided 'javax.annotation:jsr250-api:1.0'
+
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
+
+	compileOnly 'javax.annotation:jsr250-api:1.0'
 }
 
-def torBinaryDir = 'src/main/res/raw'
+dependencyVerification {
-
+	verify = [
-task downloadTorGeoIp(type: Download) {
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-	src 'https://briarproject.org/build/geoip-2017-09-06.zip'
+			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
-	dest "$torBinaryDir/geoip.zip"
+			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
-	onlyIfNewer true
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128-runtime.jar:e357a0f1d573c2f702a273992b1b6cb661734f66311854efb3778a888515c5b5',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128.jar:47b4bec6df11a1118da3953da8b9fa1e7079d6fec857faa1a3cf912e53a6fd4e',
+			'org.jacoco:org.jacoco.ant:0.7.4.201502262128:org.jacoco.ant-0.7.4.201502262128.jar:013ce2a68ba57a3c59215ae0dec4df3498c078062a38c3b94c841fc14450f283',
+			'org.jacoco:org.jacoco.core:0.7.4.201502262128:org.jacoco.core-0.7.4.201502262128.jar:ec4c74554312fac5116350164786f91b35c9e082fa4ea598bfa42b5db05d7abb',
+			'org.jacoco:org.jacoco.report:0.7.4.201502262128:org.jacoco.report-0.7.4.201502262128.jar:7a3554c605e088e7e323b1084656243f0444fa353e2f2dee1f1a4204eb64ff09',
+			'org.ow2.asm:asm-debug-all:5.0.1:asm-debug-all-5.0.1.jar:4734de5b515a454b0096db6971fb068e5f70e6f10bbee2b3bd2fdfe5d978ed57',
+	]
 }
 
-task downloadTorBinaryArm(type: Download) {
+ext.torBinaryDir = 'src/main/res/raw'
-	src 'https://briarproject.org/build/tor-0.2.9.12-arm.zip'
+ext.torVersion = '0.2.9.14'
-	dest "$torBinaryDir/tor_arm.zip"
+ext.geoipVersion = '2017-11-06'
-	onlyIfNewer true
+ext.torDownloadUrl = 'https://briarproject.org/build/'
+
+def torBinaries = [
+		"tor_arm"    : '1710ea6c47b7f4c1a88bdf4858c7893837635db10e8866854eed8d61629f50e8',
+		"tor_arm_pie": '974e6949507db8fa2ea45231817c2c3677ed4ccf5488a2252317d744b0be1917',
+		"tor_x86"    : '3a5e45b3f051fcda9353b098b7086e762ffe7ba9242f7d7c8bf6523faaa8b1e9',
+		"tor_x86_pie": 'd1d96d8ce1a4b68accf04850185780d10cd5563d3552f7e1f040f8ca32cb4e51',
+		"geoip"      : '8239b98374493529a29096e45fc5877d4d6fdad0146ad8380b291f90d61484ea'
+]
+
+def downloadBinary(name) {
+	return tasks.create("downloadBinary${name}", Download) {
+		src "${torDownloadUrl}${name}.zip"
+				.replace('tor_', "tor-${torVersion}-")
+				.replace('geoip', "geoip-${geoipVersion}")
+				.replaceAll('_', '-')
+		dest "${torBinaryDir}/${name}.zip"
+		onlyIfNewer true
+	}
 }
 
-task downloadTorBinaryArmPie(type: Download) {
+def verifyBinary(name, chksum) {
-	src 'https://briarproject.org/build/tor-0.2.9.12-arm-pie.zip'
+	return tasks.create([
-	dest "$torBinaryDir/tor_arm_pie.zip"
+			name     : "verifyBinary${name}",
-	onlyIfNewer true
+			type     : Verify,
-}
+			dependsOn: downloadBinary(name)]) {
-
+		src "${torBinaryDir}/${name}.zip"
-task downloadTorBinaryX86(type: Download) {
+		algorithm 'SHA-256'
-	src 'https://briarproject.org/build/tor-0.2.9.12-x86.zip'
+		checksum chksum
-	dest "$torBinaryDir/tor_x86.zip"
+	}
-	onlyIfNewer true
-}
-
-task downloadTorBinaryX86Pie(type: Download) {
-	src 'https://briarproject.org/build/tor-0.2.9.12-x86-pie.zip'
-	dest "$torBinaryDir/tor_x86_pie.zip"
-	onlyIfNewer true
-}
-
-task verifyTorGeoIp(type: Verify, dependsOn: 'downloadTorGeoIp') {
-	src "$torBinaryDir/geoip.zip"
-	algorithm 'SHA-256'
-	checksum 'fe49d3adb86d3c512373101422a017dbb86c85a570524663f09dd8ce143a24f3'
-}
-
-task verifyTorBinaryArm(type: Verify, dependsOn: 'downloadTorBinaryArm') {
-	src "$torBinaryDir/tor_arm.zip"
-	algorithm 'SHA-256'
-	checksum '8ed0b347ffed1d6a4d2fd14495118eb92be83e9cc06e057e15220dc288b31688'
-}
-
-task verifyTorBinaryArmPie(type: Verify, dependsOn: 'downloadTorBinaryArmPie') {
-	src "$torBinaryDir/tor_arm_pie.zip"
-	algorithm 'SHA-256'
-	checksum '64403262511c29f462ca5e7c7621bfc3c944898364d1d5ad35a016bb8a034283'
-}
-
-task verifyTorBinaryX86(type: Verify, dependsOn: 'downloadTorBinaryX86') {
-	src "$torBinaryDir/tor_x86.zip"
-	algorithm 'SHA-256'
-	checksum '61e014607a2079bcf1646289c67bff6372b1aded6e1d8d83d7791efda9a4d5ab'
-}
-
-task verifyTorBinaryX86Pie(type: Verify, dependsOn: 'downloadTorBinaryX86Pie') {
-	src "$torBinaryDir/tor_x86_pie.zip"
-	algorithm 'SHA-256'
-	checksum '18fbc98356697dd0895836ab46d5c9877d1c539193464f7db1e82a65adaaf288'
 }
 
 project.afterEvaluate {
-	preBuild.dependsOn {
+	torBinaries.every { key, value ->
-		[
+		preBuild.dependsOn.add(verifyBinary(key, value))
-				'verifyTorGeoIp',
-				'verifyTorBinaryArm',
-				'verifyTorBinaryArmPie',
-				'verifyTorBinaryX86',
-				'verifyTorBinaryX86Pie'
-		]
 	}
 }

bramble-android/src/main/AndroidManifest.xml

@@ -11,8 +11,6 @@
 	<uses-permission android:name="android.permission.INTERNET"/>
 	<uses-permission android:name="android.permission.READ_LOGS"/>
 	<uses-permission android:name="android.permission.WAKE_LOCK"/>
-	<!-- Since API 23, this is needed to add contacts via Bluetooth -->
-	<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
 
 	<application
 		android:allowBackup="false"

bramble-android/src/main/java/org/briarproject/bramble/plugin/AndroidPluginModule.java

@@ -13,6 +13,7 @@ import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.api.system.Scheduler;
 import org.briarproject.bramble.plugin.droidtooth.DroidtoothPluginFactory;
 import org.briarproject.bramble.plugin.tcp.AndroidLanTcpPluginFactory;
 import org.briarproject.bramble.plugin.tor.TorPluginFactory;
@@ -22,6 +23,7 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 
 import javax.net.SocketFactory;
 
@@ -33,19 +35,20 @@ public class AndroidPluginModule {
 
 	@Provides
 	PluginConfig providePluginConfig(@IoExecutor Executor ioExecutor,
+			@Scheduler ScheduledExecutorService scheduler,
 			AndroidExecutor androidExecutor, SecureRandom random,
 			SocketFactory torSocketFactory, BackoffFactory backoffFactory,
 			Application app, LocationUtils locationUtils, DevReporter reporter,
 			EventBus eventBus) {
 		Context appContext = app.getApplicationContext();
 		DuplexPluginFactory bluetooth = new DroidtoothPluginFactory(ioExecutor,
-				androidExecutor, appContext, random, backoffFactory);
+				androidExecutor, appContext, random, eventBus, backoffFactory);
-		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, appContext,
+		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, scheduler,
-				locationUtils, reporter, eventBus, torSocketFactory,
+				appContext, locationUtils, reporter, eventBus,
-				backoffFactory);
+				torSocketFactory, backoffFactory);
 		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(ioExecutor,
 				backoffFactory, appContext);
-		final Collection<DuplexPluginFactory> duplex =
+		Collection<DuplexPluginFactory> duplex =
 				Arrays.asList(bluetooth, tor, lan);
 		@NotNullByDefault
 		PluginConfig pluginConfig = new PluginConfig() {

bramble-android/src/main/java/org/briarproject/bramble/plugin/droidtooth/DroidtoothPlugin.java

@@ -12,6 +12,8 @@ import android.content.IntentFilter;
 import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -22,6 +24,8 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.plugin.event.DisableBluetoothEvent;
+import org.briarproject.bramble.api.plugin.event.EnableBluetoothEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.util.AndroidUtils;
@@ -63,7 +67,7 @@ import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-class DroidtoothPlugin implements DuplexPlugin {
+class DroidtoothPlugin implements DuplexPlugin, EventListener {
 
 	private static final Logger LOG =
 			Logger.getLogger(DroidtoothPlugin.class.getName());
@@ -120,12 +124,7 @@ class DroidtoothPlugin implements DuplexPlugin {
 		// with a message queue, so submit it to the AndroidExecutor
 		try {
 			adapter = androidExecutor.runOnBackgroundThread(
-					new Callable<BluetoothAdapter>() {
+					BluetoothAdapter::getDefaultAdapter).get();
-						@Override
-						public BluetoothAdapter call() throws Exception {
-							return BluetoothAdapter.getDefaultAdapter();
-						}
-					}).get();
 		} catch (InterruptedException e) {
 			Thread.currentThread().interrupt();
 			LOG.warning("Interrupted while getting BluetoothAdapter");
@@ -150,9 +149,7 @@ class DroidtoothPlugin implements DuplexPlugin {
 		} else {
 			// Enable Bluetooth if settings allow
 			if (callback.getSettings().getBoolean(PREF_BT_ENABLE, false)) {
-				wasEnabledByUs = true;
+				enableAdapter();
-				if (adapter.enable()) LOG.info("Enabling Bluetooth");
-				else LOG.info("Could not enable Bluetooth");
 			} else {
 				LOG.info("Not enabling Bluetooth");
 			}
@@ -160,40 +157,36 @@ class DroidtoothPlugin implements DuplexPlugin {
 	}
 
 	private void bind() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!isRunning()) return;
-			public void run() {
+			String address = AndroidUtils.getBluetoothAddress(appContext,
-				if (!isRunning()) return;
+					adapter);
-				String address = AndroidUtils.getBluetoothAddress(appContext,
+			if (LOG.isLoggable(INFO))
-						adapter);
+				LOG.info("Local address " + scrubMacAddress(address));
-				if (LOG.isLoggable(INFO))
+			if (!StringUtils.isNullOrEmpty(address)) {
-					LOG.info("Local address " + scrubMacAddress(address));
+				// Advertise the Bluetooth address to contacts
-				if (!StringUtils.isNullOrEmpty(address)) {
+				TransportProperties p = new TransportProperties();
-					// Advertise the Bluetooth address to contacts
+				p.put(PROP_ADDRESS, address);
-					TransportProperties p = new TransportProperties();
+				callback.mergeLocalProperties(p);
-					p.put(PROP_ADDRESS, address);
-					callback.mergeLocalProperties(p);
-				}
-				// Bind a server socket to accept connections from contacts
-				BluetoothServerSocket ss;
-				try {
-					ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
-							"RFCOMM", getUuid());
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					return;
-				}
-				if (!isRunning()) {
-					tryToClose(ss);
-					return;
-				}
-				LOG.info("Socket bound");
-				socket = ss;
-				backoff.reset();
-				callback.transportEnabled();
-				acceptContactConnections();
 			}
+			// Bind a server socket to accept connections from contacts
+			BluetoothServerSocket ss;
+			try {
+				ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
+						"RFCOMM", getUuid());
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				return;
+			}
+			if (!isRunning()) {
+				tryToClose(ss);
+				return;
+			}
+			LOG.info("Socket bound");
+			socket = ss;
+			backoff.reset();
+			callback.transportEnabled();
+			acceptContactConnections();
 		});
 	}
 
@@ -243,13 +236,27 @@ class DroidtoothPlugin implements DuplexPlugin {
 		return new DroidtoothTransportConnection(this, s);
 	}
 
+	private void enableAdapter() {
+		if (adapter != null && !adapter.isEnabled()) {
+			if (adapter.enable()) {
+				LOG.info("Enabling Bluetooth");
+				wasEnabledByUs = true;
+			} else {
+				LOG.info("Could not enable Bluetooth");
+			}
+		}
+	}
+
 	@Override
 	public void stop() {
 		running = false;
 		if (receiver != null) appContext.unregisterReceiver(receiver);
 		tryToClose(socket);
-		// Disable Bluetooth if we enabled it and it's still enabled
+		disableAdapter();
-		if (wasEnabledByUs && adapter.isEnabled()) {
+	}
+
+	private void disableAdapter() {
+		if (adapter != null && adapter.isEnabled() && wasEnabledByUs) {
 			if (adapter.disable()) LOG.info("Disabling Bluetooth");
 			else LOG.info("Could not disable Bluetooth");
 		}
@@ -278,21 +285,18 @@ class DroidtoothPlugin implements DuplexPlugin {
 		Map<ContactId, TransportProperties> remote =
 				callback.getRemoteProperties();
 		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
-			final ContactId c = e.getKey();
+			ContactId c = e.getKey();
 			if (connected.contains(c)) continue;
-			final String address = e.getValue().get(PROP_ADDRESS);
+			String address = e.getValue().get(PROP_ADDRESS);
 			if (StringUtils.isNullOrEmpty(address)) continue;
-			final String uuid = e.getValue().get(PROP_UUID);
+			String uuid = e.getValue().get(PROP_UUID);
 			if (StringUtils.isNullOrEmpty(uuid)) continue;
-			ioExecutor.execute(new Runnable() {
+			ioExecutor.execute(() -> {
-				@Override
+				if (!running) return;
-				public void run() {
+				BluetoothSocket s = connect(address, uuid);
-					if (!running) return;
+				if (s != null) {
-					BluetoothSocket s = connect(address, uuid);
+					backoff.reset();
-					if (s != null) {
+					callback.outgoingConnectionCreated(c, wrapSocket(s));
-						backoff.reset();
-						callback.outgoingConnectionCreated(c, wrapSocket(s));
-					}
 				}
 			});
 		}
@@ -347,8 +351,7 @@ class DroidtoothPlugin implements DuplexPlugin {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
-		TransportProperties p = callback.getRemoteProperties().get(c);
+		TransportProperties p = callback.getRemoteProperties(c);
-		if (p == null) return null;
 		String address = p.get(PROP_ADDRESS);
 		if (StringUtils.isNullOrEmpty(address)) return null;
 		String uuid = p.get(PROP_UUID);
@@ -413,6 +416,23 @@ class DroidtoothPlugin implements DuplexPlugin {
 		return StringUtils.macToString(mac);
 	}
 
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof EnableBluetoothEvent) {
+			enableAdapterAsync();
+		} else if (e instanceof DisableBluetoothEvent) {
+			disableAdapterAsync();
+		}
+	}
+
+	private void enableAdapterAsync() {
+		ioExecutor.execute(this::enableAdapter);
+	}
+
+	private void disableAdapterAsync() {
+		ioExecutor.execute(this::disableAdapter);
+	}
+
 	private class BluetoothStateReceiver extends BroadcastReceiver {
 
 		@Override
@@ -448,16 +468,13 @@ class DroidtoothPlugin implements DuplexPlugin {
 
 		@Override
 		public Callable<KeyAgreementConnection> listen() {
-			return new Callable<KeyAgreementConnection>() {
+			return () -> {
-				@Override
+				BluetoothSocket s = ss.accept();
-				public KeyAgreementConnection call() throws IOException {
+				if (LOG.isLoggable(INFO))
-					BluetoothSocket s = ss.accept();
+					LOG.info(ID.getString() + ": Incoming connection");
-					if (LOG.isLoggable(INFO))
+				return new KeyAgreementConnection(
-						LOG.info(ID.getString() + ": Incoming connection");
+						new DroidtoothTransportConnection(
-					return new KeyAgreementConnection(
+								DroidtoothPlugin.this, s), ID);
-							new DroidtoothTransportConnection(
-									DroidtoothPlugin.this, s), ID);
-				}
 			};
 		}
 

bramble-android/src/main/java/org/briarproject/bramble/plugin/droidtooth/DroidtoothPluginFactory.java

@@ -2,6 +2,7 @@ package org.briarproject.bramble.plugin.droidtooth;
 
 import android.content.Context;
 
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -31,15 +32,18 @@ public class DroidtoothPluginFactory implements DuplexPluginFactory {
 	private final AndroidExecutor androidExecutor;
 	private final Context appContext;
 	private final SecureRandom secureRandom;
+	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 
 	public DroidtoothPluginFactory(Executor ioExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
-			SecureRandom secureRandom, BackoffFactory backoffFactory) {
+			SecureRandom secureRandom, EventBus eventBus,
+			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.secureRandom = secureRandom;
+		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -57,7 +61,10 @@ public class DroidtoothPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		return new DroidtoothPlugin(ioExecutor, androidExecutor, appContext,
+		DroidtoothPlugin plugin = new DroidtoothPlugin(ioExecutor,
-				secureRandom, backoff, callback, MAX_LATENCY);
+				androidExecutor, appContext, secureRandom, backoff, callback,
+				MAX_LATENCY);
+		eventBus.addListener(plugin);
+		return plugin;
 	}
 }

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/TorPlugin.java

@@ -55,10 +55,16 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Scanner;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
 import java.util.zip.ZipInputStream;
@@ -69,10 +75,15 @@ import javax.net.SocketFactory;
 import static android.content.Context.CONNECTIVITY_SERVICE;
 import static android.content.Context.MODE_PRIVATE;
 import static android.content.Context.POWER_SERVICE;
+import static android.content.Intent.ACTION_SCREEN_OFF;
+import static android.content.Intent.ACTION_SCREEN_ON;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
 import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static net.freehaven.tor.control.TorControlCommands.HS_ADDRESS;
@@ -84,13 +95,13 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_NEVER;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_WIFI;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
+import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubOnion;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
-	private static final String PROP_ONION = "onion";
 	private static final String[] EVENTS = {
 			"CIRC", "ORCONN", "HS_DESC", "NOTICE", "WARN", "ERR"
 	};
@@ -101,6 +112,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			Logger.getLogger(TorPlugin.class.getName());
 
 	private final Executor ioExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
 	private final DevReporter reporter;
@@ -113,6 +125,9 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final File torDirectory, torFile, geoIpFile, configFile;
 	private final File doneFile, cookieFile;
 	private final PowerManager.WakeLock wakeLock;
+	private final Lock connectionStatusLock;
+	private final AtomicReference<Future<?>> connectivityCheck =
+			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	private volatile boolean running = false;
@@ -121,12 +136,13 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private volatile TorControlConnection controlConnection = null;
 	private volatile BroadcastReceiver networkStateReceiver = null;
 
-	TorPlugin(Executor ioExecutor, Context appContext,
+	TorPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
-			LocationUtils locationUtils, DevReporter reporter,
+			Context appContext, LocationUtils locationUtils,
-			SocketFactory torSocketFactory, Backoff backoff,
+			DevReporter reporter, SocketFactory torSocketFactory,
-			DuplexPluginCallback callback, String architecture, int maxLatency,
+			Backoff backoff, DuplexPluginCallback callback,
-			int maxIdleTime) {
+			String architecture, int maxLatency, int maxIdleTime) {
 		this.ioExecutor = ioExecutor;
+		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
 		this.reporter = reporter;
@@ -148,8 +164,10 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
 		Object o = appContext.getSystemService(POWER_SERVICE);
 		PowerManager pm = (PowerManager) o;
-		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "TorPlugin");
+		// This tag will prevent Huawei's powermanager from killing us.
+		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "LocationManagerService");
 		wakeLock.setReferenceCounted(false);
+		connectionStatusLock = new ReentrantLock();
 	}
 
 	@Override
@@ -202,11 +220,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (LOG.isLoggable(INFO)) {
 			Scanner stdout = new Scanner(torProcess.getInputStream());
 			Scanner stderr = new Scanner(torProcess.getErrorStream());
-			while (stdout.hasNextLine() || stderr.hasNextLine()){
+			while (stdout.hasNextLine() || stderr.hasNextLine()) {
-				if(stdout.hasNextLine()) {
+				if (stdout.hasNextLine()) {
 					LOG.info(stdout.nextLine());
 				}
-				if(stderr.hasNextLine()){
+				if (stderr.hasNextLine()) {
 					LOG.info(stderr.nextLine());
 				}
 			}
@@ -255,7 +273,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 		// Register to receive network status events
 		networkStateReceiver = new NetworkStateReceiver();
-		IntentFilter filter = new IntentFilter(CONNECTIVITY_ACTION);
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(CONNECTIVITY_ACTION);
+		filter.addAction(ACTION_SCREEN_ON);
+		filter.addAction(ACTION_SCREEN_OFF);
+		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
 		appContext.registerReceiver(networkStateReceiver, filter);
 		// Bind a server socket to receive incoming hidden service connections
 		bind();
@@ -368,57 +390,45 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void sendDevReports() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			// TODO: Trigger this with a TransportEnabledEvent
-			public void run() {
+			File reportDir = AndroidUtils.getReportDir(appContext);
-				// TODO: Trigger this with a TransportEnabledEvent
+			reporter.sendReports(reportDir);
-				File reportDir = AndroidUtils.getReportDir(appContext);
-				reporter.sendReports(reportDir);
-			}
 		});
 	}
 
 	private void bind() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			// If there's already a port number stored in config, reuse it
-			public void run() {
+			String portString = callback.getSettings().get(PREF_TOR_PORT);
-				// If there's already a port number stored in config, reuse it
+			int port;
-				String portString = callback.getSettings().get(PREF_TOR_PORT);
+			if (StringUtils.isNullOrEmpty(portString)) port = 0;
-				int port;
+			else port = Integer.parseInt(portString);
-				if (StringUtils.isNullOrEmpty(portString)) port = 0;
+			// Bind a server socket to receive connections from Tor
-				else port = Integer.parseInt(portString);
+			ServerSocket ss = null;
-				// Bind a server socket to receive connections from Tor
+			try {
-				ServerSocket ss = null;
+				ss = new ServerSocket();
-				try {
+				ss.bind(new InetSocketAddress("127.0.0.1", port));
-					ss = new ServerSocket();
+			} catch (IOException e) {
-					ss.bind(new InetSocketAddress("127.0.0.1", port));
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				} catch (IOException e) {
+				tryToClose(ss);
-					if (LOG.isLoggable(WARNING))
+				return;
-						LOG.log(WARNING, e.toString(), e);
-					tryToClose(ss);
-					return;
-				}
-				if (!running) {
-					tryToClose(ss);
-					return;
-				}
-				socket = ss;
-				// Store the port number
-				final String localPort = String.valueOf(ss.getLocalPort());
-				Settings s = new Settings();
-				s.put(PREF_TOR_PORT, localPort);
-				callback.mergeSettings(s);
-				// Create a hidden service if necessary
-				ioExecutor.execute(new Runnable() {
-					@Override
-					public void run() {
-						publishHiddenService(localPort);
-					}
-				});
-				backoff.reset();
-				// Accept incoming hidden service connections from Tor
-				acceptContactConnections(ss);
 			}
+			if (!running) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			// Store the port number
+			String localPort = String.valueOf(ss.getLocalPort());
+			Settings s = new Settings();
+			s.put(PREF_TOR_PORT, localPort);
+			callback.mergeSettings(s);
+			// Create a hidden service if necessary
+			ioExecutor.execute(() -> publishHiddenService(localPort));
+			backoff.reset();
+			// Accept incoming hidden service connections from Tor
+			acceptContactConnections(ss);
 		});
 	}
 
@@ -538,20 +548,21 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	public void poll(Collection<ContactId> connected) {
 		if (!isRunning()) return;
 		backoff.increment();
-		// TODO: Pass properties to connectAndCallBack()
+		Map<ContactId, TransportProperties> remote =
-		for (ContactId c : callback.getRemoteProperties().keySet())
+				callback.getRemoteProperties();
-			if (!connected.contains(c)) connectAndCallBack(c);
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (!connected.contains(c)) connectAndCallBack(c, e.getValue());
+		}
 	}
 
-	private void connectAndCallBack(final ContactId c) {
+	private void connectAndCallBack(ContactId c, TransportProperties p) {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!isRunning()) return;
-			public void run() {
+			DuplexTransportConnection d = createConnection(p);
-				DuplexTransportConnection d = createConnection(c);
+			if (d != null) {
-				if (d != null) {
+				backoff.reset();
-					backoff.reset();
+				callback.outgoingConnectionCreated(c, d);
-					callback.outgoingConnectionCreated(c, d);
-				}
 			}
 		});
 	}
@@ -559,8 +570,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
-		TransportProperties p = callback.getRemoteProperties().get(c);
+		return createConnection(callback.getRemoteProperties(c));
-		if (p == null) return null;
+	}
+
+	@Nullable
+	private DuplexTransportConnection createConnection(TransportProperties p) {
 		String onion = p.get(PROP_ONION);
 		if (StringUtils.isNullOrEmpty(onion)) return null;
 		if (!ONION.matcher(onion).matches()) {
@@ -624,6 +638,8 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void orConnStatus(String status, String orName) {
 		if (LOG.isLoggable(INFO)) LOG.info("OR connection " + status);
+		if (status.equals("CLOSED") || status.equals("FAILED"))
+			updateConnectionStatus(); // Check whether we've lost connectivity
 	}
 
 	@Override
@@ -663,7 +679,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 
 		@Override
-		public void onEvent(int event, String path) {
+		public void onEvent(int event, @Nullable String path) {
 			stopWatching();
 			latch.countDown();
 		}
@@ -681,60 +697,75 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void updateConnectionStatus() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!running) return;
-			public void run() {
+			try {
-				if (!running) return;
+				connectionStatusLock.lock();
-
+				updateConnectionStatusLocked();
-				Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
+			} finally {
-				ConnectivityManager cm = (ConnectivityManager) o;
+				connectionStatusLock.unlock();
-				NetworkInfo net = cm.getActiveNetworkInfo();
-				boolean online = net != null && net.isConnected();
-				boolean wifi = online && net.getType() == TYPE_WIFI;
-				String country = locationUtils.getCurrentCountry();
-				boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
-						country);
-				Settings s = callback.getSettings();
-				int network = s.getInt(PREF_TOR_NETWORK,
-						PREF_TOR_NETWORK_ALWAYS);
-
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Online: " + online + ", wifi: " + wifi);
-					if ("".equals(country)) LOG.info("Country code unknown");
-					else LOG.info("Country code: " + country);
-				}
-
-				try {
-					if (!online) {
-						LOG.info("Disabling network, device is offline");
-						enableNetwork(false);
-					} else if (blocked) {
-						LOG.info("Disabling network, country is blocked");
-						enableNetwork(false);
-					} else if (network == PREF_TOR_NETWORK_NEVER
-							|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
-						LOG.info("Disabling network due to data setting");
-						enableNetwork(false);
-					} else {
-						LOG.info("Enabling network");
-						enableNetwork(true);
-					}
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-				}
 			}
 		});
 	}
 
+	// Locking: connectionStatusLock
+	private void updateConnectionStatusLocked() {
+		Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
+		ConnectivityManager cm = (ConnectivityManager) o;
+		NetworkInfo net = cm.getActiveNetworkInfo();
+		boolean online = net != null && net.isConnected();
+		boolean wifi = online && net.getType() == TYPE_WIFI;
+		String country = locationUtils.getCurrentCountry();
+		boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
+				country);
+		Settings s = callback.getSettings();
+		int network = s.getInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_ALWAYS);
+
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Online: " + online + ", wifi: " + wifi);
+			if ("".equals(country)) LOG.info("Country code unknown");
+			else LOG.info("Country code: " + country);
+		}
+
+		try {
+			if (!online) {
+				LOG.info("Disabling network, device is offline");
+				enableNetwork(false);
+			} else if (blocked) {
+				LOG.info("Disabling network, country is blocked");
+				enableNetwork(false);
+			} else if (network == PREF_TOR_NETWORK_NEVER
+					|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
+				LOG.info("Disabling network due to data setting");
+				enableNetwork(false);
+			} else {
+				LOG.info("Enabling network");
+				enableNetwork(true);
+			}
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
+	private void scheduleConnectionStatusUpdate() {
+		Future<?> newConnectivityCheck =
+				scheduler.schedule(this::updateConnectionStatus, 1, MINUTES);
+		Future<?> oldConnectivityCheck =
+				connectivityCheck.getAndSet(newConnectivityCheck);
+		if (oldConnectivityCheck != null) oldConnectivityCheck.cancel(false);
+	}
+
 	private class NetworkStateReceiver extends BroadcastReceiver {
 
 		@Override
 		public void onReceive(Context ctx, Intent i) {
 			if (!running) return;
-			if (CONNECTIVITY_ACTION.equals(i.getAction())) {
+			String action = i.getAction();
-				LOG.info("Detected connectivity change");
+			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
-				updateConnectionStatus();
+			updateConnectionStatus();
+			if (ACTION_SCREEN_ON.equals(action)
+					|| ACTION_SCREEN_OFF.equals(action)) {
+				scheduleConnectionStatusUpdate();
 			}
 		}
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/TorPluginFactory.java

@@ -17,6 +17,7 @@ import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.util.AndroidUtils;
 
 import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.Immutable;
@@ -36,6 +37,7 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
 	private final DevReporter reporter;
@@ -43,11 +45,13 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private final SocketFactory torSocketFactory;
 	private final BackoffFactory backoffFactory;
 
-	public TorPluginFactory(Executor ioExecutor, Context appContext,
+	public TorPluginFactory(Executor ioExecutor,
+			ScheduledExecutorService scheduler, Context appContext,
 			LocationUtils locationUtils, DevReporter reporter,
 			EventBus eventBus, SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
+		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
 		this.reporter = reporter;
@@ -89,9 +93,9 @@ public class TorPluginFactory implements DuplexPluginFactory {
 
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		TorPlugin plugin = new TorPlugin(ioExecutor, appContext, locationUtils,
+		TorPlugin plugin = new TorPlugin(ioExecutor, scheduler, appContext,
-				reporter, torSocketFactory, backoff, callback, architecture,
+				locationUtils, reporter, torSocketFactory, backoff, callback,
-				MAX_LATENCY, MAX_IDLE_TIME);
+				architecture, MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-android/src/main/java/org/briarproject/bramble/system/AndroidExecutorImpl.java

@@ -27,14 +27,11 @@ class AndroidExecutorImpl implements AndroidExecutor {
 	@Inject
 	AndroidExecutorImpl(Application app) {
 		uiHandler = new Handler(app.getApplicationContext().getMainLooper());
-		loop = new Runnable() {
+		loop = () -> {
-			@Override
+			Looper.prepare();
-			public void run() {
+			backgroundHandler = new Handler();
-				Looper.prepare();
+			startLatch.countDown();
-				backgroundHandler = new Handler();
+			Looper.loop();
-				startLatch.countDown();
-				Looper.loop();
-			}
 		};
 	}
 

bramble-api/build.gradle

@@ -1,30 +1,39 @@
-apply plugin: 'java'
+apply plugin: 'java-library'
-sourceCompatibility = 1.6
+sourceCompatibility = 1.8
-targetCompatibility = 1.6
+targetCompatibility = 1.8
 
 apply plugin: 'witness'
 
 dependencies {
-	compile "com.google.dagger:dagger:2.0.2"
+	implementation "com.google.dagger:dagger:2.0.2"
-	compile 'com.google.dagger:dagger-compiler:2.0.2'
+	implementation 'com.google.code.findbugs:jsr305:3.0.2'
-	compile 'com.google.code.findbugs:jsr305:3.0.2'
 
-	testCompile 'junit:junit:4.12'
+	testImplementation 'junit:junit:4.12'
-	testCompile "org.jmock:jmock:2.8.2"
+	testImplementation "org.jmock:jmock:2.8.2"
-	testCompile "org.jmock:jmock-junit4:2.8.2"
+	testImplementation "org.jmock:jmock-junit4:2.8.2"
-	testCompile "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.jmock:jmock-legacy:2.8.2"
-	testCompile "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
-	testCompile "org.hamcrest:hamcrest-core:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
 }
 
 dependencyVerification {
 	verify = [
-			'com.google.dagger:dagger:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-			'com.google.dagger:dagger-compiler:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-			'com.google.code.findbugs:jsr305:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-			'javax.inject:javax.inject:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
-			'com.google.dagger:dagger-producers:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
-			'com.google.guava:guava:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
+			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
 	]
 }
 
@@ -39,3 +48,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

bramble-api/src/main/java/org/briarproject/bramble/api/client/BdfMessageContext.java

@@ -23,7 +23,7 @@ public class BdfMessageContext {
 	}
 
 	public BdfMessageContext(BdfDictionary dictionary) {
-		this(dictionary, Collections.<MessageId>emptyList());
+		this(dictionary, Collections.emptyList());
 	}
 
 	public BdfDictionary getDictionary() {

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfDictionary.java

@@ -4,11 +4,14 @@ import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
 import java.util.Map;
-import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.Map.Entry;
+import java.util.TreeMap;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
-public class BdfDictionary extends ConcurrentSkipListMap<String, Object> {
+@NotThreadSafe
+public class BdfDictionary extends TreeMap<String, Object> {
 
 	public static final Object NULL_VALUE = new Object();
 

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfList.java

@@ -3,15 +3,17 @@ package org.briarproject.bramble.api.data;
 import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Vector;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
 import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
 
-public class BdfList extends Vector<Object> {
+@NotThreadSafe
+public class BdfList extends ArrayList<Object> {
 
 	/**
 	 * Factory method for constructing lists inline.

bramble-api/src/main/java/org/briarproject/bramble/api/db/DataTooNewException.java

@@ -0,0 +1,7 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * Thrown when the database uses a newer schema than the current code.
+ */
+public class DataTooNewException extends DbException {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/db/DataTooOldException.java

@@ -0,0 +1,8 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * Thrown when the database uses an older schema than the current code and
+ * cannot be migrated.
+ */
+public class DataTooOldException extends DbException {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java

@@ -37,6 +37,11 @@ public interface DatabaseComponent {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
+	 *
+	 * @throws DataTooNewException if the data uses a newer schema than the
+	 * current code
+	 * @throws DataTooOldException if the data uses an older schema than the
+	 * current code and cannot be migrated
 	 */
 	boolean open() throws DbException;
 
@@ -122,8 +127,9 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Deletes the message with the given ID. The message ID and any other
+	 * Deletes the message with the given ID. Unlike
-	 * associated data are not deleted.
+	 * {@link #removeMessage(Transaction, MessageId)}, the message ID and any
+	 * other associated data are not deleted.
 	 */
 	void deleteMessage(Transaction txn, MessageId m) throws DbException;
 
@@ -452,6 +458,11 @@ public interface DatabaseComponent {
 	 */
 	void removeLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
+	/**
+	 * Removes a message (and all associated state) from the database.
+	 */
+	void removeMessage(Transaction txn, MessageId m) throws DbException;
+
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/db/Metadata.java

@@ -1,11 +1,11 @@
 package org.briarproject.bramble.api.db;
 
-import java.util.Hashtable;
+import java.util.TreeMap;
 
-import javax.annotation.concurrent.ThreadSafe;
+import javax.annotation.concurrent.NotThreadSafe;
 
-@ThreadSafe
+@NotThreadSafe
-public class Metadata extends Hashtable<String, byte[]> {
+public class Metadata extends TreeMap<String, byte[]> {
 
 	/**
 	 * Special value to indicate that a key is being removed.

bramble-api/src/main/java/org/briarproject/bramble/api/db/Transaction.java

@@ -45,7 +45,7 @@ public class Transaction {
 	 * committed.
 	 */
 	public void attach(Event e) {
-		if (events == null) events = new ArrayList<Event>();
+		if (events == null) events = new ArrayList<>();
 		events.add(e);
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/LanTcpConstants.java

@@ -4,5 +4,10 @@ public interface LanTcpConstants {
 
 	TransportId ID = new TransportId("org.briarproject.bramble.lan");
 
+	// a transport property (shared with contacts)
+	String PROP_IP_PORTS = "ipPorts";
+
+	// a local setting
 	String PREF_LAN_IP_PORTS = "ipPorts";
+
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/PluginCallback.java

@@ -29,6 +29,11 @@ public interface PluginCallback {
 	 */
 	Map<ContactId, TransportProperties> getRemoteProperties();
 
+	/**
+	 * Returns the plugin's remote transport properties for the given contact.
+	 */
+	TransportProperties getRemoteProperties(ContactId c);
+
 	/**
 	 * Merges the given settings with the namespaced settings
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/TorConstants.java

@@ -4,6 +4,8 @@ public interface TorConstants {
 
 	TransportId ID = new TransportId("org.briarproject.bramble.tor");
 
+	String PROP_ONION = "onion";
+
 	int SOCKS_PORT = 59050;
 	int CONTROL_PORT = 59051;
 
@@ -16,4 +18,5 @@ public interface TorConstants {
 	int PREF_TOR_NETWORK_NEVER = 0;
 	int PREF_TOR_NETWORK_WIFI = 1;
 	int PREF_TOR_NETWORK_ALWAYS = 2;
+
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/DisableBluetoothEvent.java

@@ -0,0 +1,15 @@
+package org.briarproject.bramble.api.plugin.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that asks the Bluetooth plugin to disable the Bluetooth adapter if
+ * we previously enabled it.
+ */
+@Immutable
+@NotNullByDefault
+public class DisableBluetoothEvent extends Event {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/EnableBluetoothEvent.java

@@ -0,0 +1,14 @@
+package org.briarproject.bramble.api.plugin.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event asks the Bluetooth plugin to enable the Bluetooth adapter.
+ */
+@Immutable
+@NotNullByDefault
+public class EnableBluetoothEvent extends Event {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/properties/TransportPropertyManager.java

@@ -33,7 +33,7 @@ public interface TransportPropertyManager {
 	/**
 	 * Returns the local transport properties for all transports.
 	 * <br/>
-	 * Read-Only
+	 * TODO: Transaction can be read-only when code is simplified
 	 */
 	Map<TransportId, TransportProperties> getLocalProperties(Transaction txn)
 			throws DbException;
@@ -49,6 +49,13 @@ public interface TransportPropertyManager {
 	Map<ContactId, TransportProperties> getRemoteProperties(TransportId t)
 			throws DbException;
 
+	/**
+	 * Returns the remote transport properties for the given contact and
+	 * transport.
+	 */
+	TransportProperties getRemoteProperties(ContactId c, TransportId t)
+			throws DbException;
+
 	/**
 	 * Merges the given properties with the existing local properties for the
 	 * given transport.

bramble-api/src/main/java/org/briarproject/bramble/api/sync/MessageContext.java

@@ -22,7 +22,7 @@ public class MessageContext {
 	}
 
 	public MessageContext(Metadata metadata) {
-		this(metadata, Collections.<MessageId>emptyList());
+		this(metadata, Collections.emptyList());
 	}
 
 	public Metadata getMetadata() {

bramble-api/src/main/java/org/briarproject/bramble/util/StringUtils.java

@@ -8,6 +8,7 @@ import java.nio.charset.CharacterCodingException;
 import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 import java.util.Collection;
+import java.util.Random;
 import java.util.regex.Pattern;
 
 import javax.annotation.Nullable;
@@ -27,6 +28,7 @@ public class StringUtils {
 			'0', '1', '2', '3', '4', '5', '6', '7',
 			'8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
 	};
+	private static final Random random = new Random();
 
 	public static boolean isNullOrEmpty(@Nullable String s) {
 		return s == null || s.length() == 0;
@@ -139,4 +141,12 @@ public class StringUtils {
 		}
 		return s.toString();
 	}
+
+	public static String getRandomString(int length) {
+		char[] c = new char[length];
+		for (int i = 0; i < length; i++)
+			c[i] = (char) ('a' + random.nextInt(26));
+		return new String(c);
+	}
+
 }

bramble-api/src/test/java/org/briarproject/bramble/test/BrambleMockTestCase.java

@@ -3,8 +3,7 @@ package org.briarproject.bramble.test;
 import org.jmock.Mockery;
 import org.junit.After;
 
-public abstract class BrambleMockTestCase extends
+public abstract class BrambleMockTestCase extends BrambleTestCase {
-		BrambleTestCase {
 
 	protected final Mockery context = new Mockery();
 

bramble-api/src/test/java/org/briarproject/bramble/test/BrambleTestCase.java

@@ -8,12 +8,9 @@ public abstract class BrambleTestCase {
 
 	public BrambleTestCase() {
 		// Ensure exceptions thrown on worker threads cause tests to fail
-		UncaughtExceptionHandler fail = new UncaughtExceptionHandler() {
+		UncaughtExceptionHandler fail = (thread, throwable) -> {
-			@Override
+			throwable.printStackTrace();
-			public void uncaughtException(Thread thread, Throwable throwable) {
+			fail();
-				throwable.printStackTrace();
-				fail();
-			}
 		};
 		Thread.setDefaultUncaughtExceptionHandler(fail);
 	}

bramble-api/src/test/java/org/briarproject/bramble/test/TestUtils.java

@@ -2,12 +2,27 @@ package org.briarproject.bramble.test;
 
 import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.util.IoUtils;
 
 import java.io.File;
 import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+import static org.briarproject.bramble.util.StringUtils.getRandomString;
+
 public class TestUtils {
 
 	private static final AtomicInteger nextTestDir =
@@ -34,15 +49,54 @@ public class TestUtils {
 		return getRandomBytes(UniqueId.LENGTH);
 	}
 
-	public static String getRandomString(int length) {
-		char[] c = new char[length];
-		for (int i = 0; i < length; i++)
-			c[i] = (char) ('a' + random.nextInt(26));
-		return new String(c);
-	}
-
 	public static SecretKey getSecretKey() {
 		return new SecretKey(getRandomBytes(SecretKey.LENGTH));
 	}
 
+	public static LocalAuthor getLocalAuthor() {
+		return getLocalAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+	}
+
+	public static LocalAuthor getLocalAuthor(int nameLength) {
+		AuthorId id = new AuthorId(getRandomId());
+		String name = getRandomString(nameLength);
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		long created = System.currentTimeMillis();
+		return new LocalAuthor(id, name, publicKey, privateKey, created);
+	}
+
+	public static Author getAuthor() {
+		return getAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+	}
+
+	public static Author getAuthor(int nameLength) {
+		AuthorId id = new AuthorId(getRandomId());
+		String name = getRandomString(nameLength);
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		return new Author(id, name, publicKey);
+	}
+
+	public static Group getGroup(ClientId clientId) {
+		int descriptorLength = 1 + random.nextInt(MAX_GROUP_DESCRIPTOR_LENGTH);
+		return getGroup(clientId, descriptorLength);
+	}
+
+	public static Group getGroup(ClientId clientId, int descriptorLength) {
+		GroupId groupId = new GroupId(getRandomId());
+		byte[] descriptor = getRandomBytes(descriptorLength);
+		return new Group(groupId, clientId, descriptor);
+	}
+
+	public static Message getMessage(GroupId groupId) {
+		int bodyLength = 1 + random.nextInt(MAX_MESSAGE_BODY_LENGTH);
+		return getMessage(groupId, MESSAGE_HEADER_LENGTH + bodyLength);
+	}
+
+	public static Message getMessage(GroupId groupId, int rawLength) {
+		MessageId id = new MessageId(getRandomId());
+		byte[] raw = getRandomBytes(rawLength);
+		long timestamp = System.currentTimeMillis();
+		return new Message(id, groupId, timestamp, raw);
+	}
 }

bramble-core/build.gradle

@@ -1,28 +1,54 @@
-plugins {
+apply plugin: 'java-library'
-	id 'java'
+sourceCompatibility = 1.8
-	id 'net.ltgt.apt' version '0.9'
+targetCompatibility = 1.8
-	id 'idea'
-}
-
-sourceCompatibility = 1.6
-targetCompatibility = 1.6
 
+apply plugin: 'net.ltgt.apt'
+apply plugin: 'idea'
 apply plugin: 'witness'
 
 dependencies {
-	compile project(':bramble-api')
+	implementation project(path: ':bramble-api', configuration: 'default')
-	compile 'com.madgag.spongycastle:core:1.56.0.0'
+	implementation 'com.madgag.spongycastle:core:1.58.0.0'
-	compile 'com.h2database:h2:1.4.192' // This is the last version that supports Java 1.6
+	implementation 'com.h2database:h2:1.4.192' // This is the last version that supports Java 1.6
-	compile 'org.bitlet:weupnp:0.1.4'
+	implementation 'org.bitlet:weupnp:0.1.4'
 
-	testCompile project(path: ':bramble-api', configuration: 'testOutput')
+	apt 'com.google.dagger:dagger-compiler:2.0.2'
+
+	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
+	testImplementation 'junit:junit:4.12'
+	testImplementation "org.jmock:jmock:2.8.2"
+	testImplementation "org.jmock:jmock-junit4:2.8.2"
+	testImplementation "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
+
+	testApt 'com.google.dagger:dagger-compiler:2.0.2'
 }
 
 dependencyVerification {
 	verify = [
-			'com.madgag.spongycastle:core:5e791b0eaa9e0c4594231b44f616a52adddb7dccedeb0ad9ad74887e19499a23',
+			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-			'com.h2database:h2:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-			'org.bitlet:weupnp:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
+			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
+			'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
+			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
 	]
 }
 
@@ -37,3 +63,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

bramble-core/src/main/java/org/briarproject/bramble/PoliteExecutor.java

@@ -24,7 +24,7 @@ public class PoliteExecutor implements Executor {
 
 	private final Object lock = new Object();
 	@GuardedBy("lock")
-	private final Queue<Runnable> queue = new LinkedList<Runnable>();
+	private final Queue<Runnable> queue = new LinkedList<>();
 	private final Executor delegate;
 	private final int maxConcurrentTasks;
 	private final Logger log;
@@ -48,20 +48,17 @@ public class PoliteExecutor implements Executor {
 	}
 
 	@Override
-	public void execute(final Runnable r) {
+	public void execute(Runnable r) {
-		final long submitted = System.currentTimeMillis();
+		long submitted = System.currentTimeMillis();
-		Runnable wrapped = new Runnable() {
+		Runnable wrapped = () -> {
-			@Override
+			if (log.isLoggable(LOG_LEVEL)) {
-			public void run() {
+				long queued = System.currentTimeMillis() - submitted;
-				if (log.isLoggable(LOG_LEVEL)) {
+				log.log(LOG_LEVEL, "Queue time " + queued + " ms");
-					long queued = System.currentTimeMillis() - submitted;
+			}
-					log.log(LOG_LEVEL, "Queue time " + queued + " ms");
+			try {
-				}
+				r.run();
-				try {
+			} finally {
-					r.run();
+				scheduleNext();
-				} finally {
-					scheduleNext();
-				}
 			}
 		};
 		synchronized (lock) {

bramble-core/src/main/java/org/briarproject/bramble/TimeLoggingExecutor.java

@@ -28,19 +28,16 @@ public class TimeLoggingExecutor extends ThreadPoolExecutor {
 	}
 
 	@Override
-	public void execute(final Runnable r) {
+	public void execute(Runnable r) {
 		if (log.isLoggable(LOG_LEVEL)) {
-			final long submitted = System.currentTimeMillis();
+			long submitted = System.currentTimeMillis();
-			super.execute(new Runnable() {
+			super.execute(() -> {
-				@Override
+				long started = System.currentTimeMillis();
-				public void run() {
+				long queued = started - submitted;
-					long started = System.currentTimeMillis();
+				log.log(LOG_LEVEL, "Queue time " + queued + " ms");
-					long queued = started - submitted;
+				r.run();
-					log.log(LOG_LEVEL, "Queue time " + queued + " ms");
+				long executing = System.currentTimeMillis() - started;
-					r.run();
+				log.log(LOG_LEVEL, "Execution time " + executing + " ms");
-					long executing = System.currentTimeMillis() - started;
-					log.log(LOG_LEVEL, "Execution time " + executing + " ms");
-				}
 			});
 		} else {
 			super.execute(r);

bramble-core/src/main/java/org/briarproject/bramble/client/ClientHelperImpl.java

@@ -201,8 +201,7 @@ class ClientHelperImpl implements ClientHelper {
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			Transaction txn, GroupId g) throws DbException, FormatException {
 		Map<MessageId, Metadata> raw = db.getMessageMetadata(txn, g);
-		Map<MessageId, BdfDictionary> parsed =
+		Map<MessageId, BdfDictionary> parsed = new HashMap<>(raw.size());
-				new HashMap<MessageId, BdfDictionary>(raw.size());
 		for (Entry<MessageId, Metadata> e : raw.entrySet())
 			parsed.put(e.getKey(), metadataParser.parse(e.getValue()));
 		return parsed;
@@ -229,8 +228,7 @@ class ClientHelperImpl implements ClientHelper {
 			FormatException {
 		Metadata metadata = metadataEncoder.encode(query);
 		Map<MessageId, Metadata> raw = db.getMessageMetadata(txn, g, metadata);
-		Map<MessageId, BdfDictionary> parsed =
+		Map<MessageId, BdfDictionary> parsed = new HashMap<>(raw.size());
-				new HashMap<MessageId, BdfDictionary>(raw.size());
 		for (Entry<MessageId, Metadata> e : raw.entrySet())
 			parsed.put(e.getKey(), metadataParser.parse(e.getValue()));
 		return parsed;

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactExchangeTaskImpl.java

@@ -184,12 +184,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			// Close the outgoing stream and expect EOF on the incoming stream
 			w.close();
 			if (!r.eof()) LOG.warning("Unexpected data at end of connection");
-		} catch (GeneralSecurityException e) {
+		} catch (GeneralSecurityException | IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			listener.contactExchangeFailed();
-			tryToClose(conn, true);
-			return;
-		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			listener.contactExchangeFailed();
 			tryToClose(conn, true);
@@ -276,8 +271,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 	private Map<TransportId, TransportProperties> receiveTransportProperties(
 			BdfReader r) throws IOException {
-		Map<TransportId, TransportProperties> remote =
+		Map<TransportId, TransportProperties> remote = new HashMap<>();
-				new HashMap<TransportId, TransportProperties>();
 		r.readListStart();
 		while (!r.hasListEnd()) {
 			r.readListStart();

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactManagerImpl.java

@@ -34,8 +34,8 @@ class ContactManagerImpl implements ContactManager {
 	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager) {
 		this.db = db;
 		this.keyManager = keyManager;
-		addHooks = new CopyOnWriteArrayList<AddContactHook>();
+		addHooks = new CopyOnWriteArrayList<>();
-		removeHooks = new CopyOnWriteArrayList<RemoveContactHook>();
+		removeHooks = new CopyOnWriteArrayList<>();
 	}
 
 	@Override
@@ -125,7 +125,7 @@ class ContactManagerImpl implements ContactManager {
 		} finally {
 			db.endTransaction(txn);
 		}
-		List<Contact> active = new ArrayList<Contact>(contacts.size());
+		List<Contact> active = new ArrayList<>(contacts.size());
 		for (Contact c : contacts) if (c.isActive()) active.add(c);
 		return active;
 	}

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoComponentImpl.java

@@ -602,8 +602,8 @@ class CryptoComponentImpl implements CryptoComponent {
 
 	// Package access for testing
 	int chooseIterationCount(int targetMillis) {
-		List<Long> quickSamples = new ArrayList<Long>(PBKDF_SAMPLES);
+		List<Long> quickSamples = new ArrayList<>(PBKDF_SAMPLES);
-		List<Long> slowSamples = new ArrayList<Long>(PBKDF_SAMPLES);
+		List<Long> slowSamples = new ArrayList<>(PBKDF_SAMPLES);
 		long iterationNanos = 0, initNanos = 0;
 		while (iterationNanos <= 0 || initNanos <= 0) {
 			// Sample the running time with one iteration and two iterations

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoModule.java

@@ -48,7 +48,7 @@ public class CryptoModule {
 
 	public CryptoModule() {
 		// Use an unbounded queue
-		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

bramble-core/src/main/java/org/briarproject/bramble/crypto/PasswordStrengthEstimatorImpl.java

@@ -16,7 +16,7 @@ class PasswordStrengthEstimatorImpl implements PasswordStrengthEstimator {
 
 	@Override
 	public float estimateStrength(String password) {
-		HashSet<Character> unique = new HashSet<Character>();
+		HashSet<Character> unique = new HashSet<>();
 		int length = password.length();
 		for (int i = 0; i < length; i++) unique.add(password.charAt(i));
 		return Math.min(1, (float) unique.size() / STRONG_UNIQUE_CHARS);

bramble-core/src/main/java/org/briarproject/bramble/db/Database.java

@@ -2,6 +2,8 @@ package org.briarproject.bramble.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DataTooNewException;
+import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.identity.Author;
@@ -37,6 +39,11 @@ interface Database<T> {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
+	 *
+	 * @throws DataTooNewException if the data uses a newer schema than the
+	 * current code
+	 * @throws DataTooOldException if the data uses an older schema than the
+	 * current code and cannot be migrated
 	 */
 	boolean open() throws DbException;
 

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java

@@ -90,8 +90,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	private final ReentrantReadWriteLock lock =
 			new ReentrantReadWriteLock(true);
 
-	private volatile int shutdownHandle = -1;
-
 	@Inject
 	DatabaseComponentImpl(Database<T> db, Class<T> txnClass, EventBus eventBus,
 			ShutdownManager shutdown) {
@@ -103,26 +101,20 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public boolean open() throws DbException {
-		Runnable shutdownHook = new Runnable() {
-			@Override
-			public void run() {
-				try {
-					close();
-				} catch (DbException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-				}
-			}
-		};
 		boolean reopened = db.open();
-		shutdownHandle = shutdown.addShutdownHook(shutdownHook);
+		shutdown.addShutdownHook(() -> {
+			try {
+				close();
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			}
+		});
 		return reopened;
 	}
 
 	@Override
 	public void close() throws DbException {
 		if (closed.getAndSet(true)) return;
-		shutdown.removeShutdownHook(shutdownHandle);
 		db.close();
 	}
 
@@ -141,11 +133,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 		try {
 			return new Transaction(db.startTransaction(), readOnly);
-		} catch (DbException e) {
+		} catch (DbException | RuntimeException e) {
-			if (readOnly) lock.readLock().unlock();
-			else lock.writeLock().unlock();
-			throw e;
-		} catch (RuntimeException e) {
 			if (readOnly) lock.readLock().unlock();
 			else lock.writeLock().unlock();
 			throw e;
@@ -331,7 +319,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
 		Collection<MessageId> ids = db.getMessagesToSend(txn, c, maxLength);
-		List<byte[]> messages = new ArrayList<byte[]>(ids.size());
+		List<byte[]> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
 			messages.add(db.getRawMessage(txn, m));
 			db.updateExpiryTime(txn, c, m, maxLatency);
@@ -381,7 +369,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		Collection<MessageId> ids = db.getRequestedMessagesToSend(txn, c,
 				maxLength);
-		List<byte[]> messages = new ArrayList<byte[]>(ids.size());
+		List<byte[]> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
 			messages.add(db.getRawMessage(txn, m));
 			db.updateExpiryTime(txn, c, m, maxLatency);
@@ -661,7 +649,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
-		Collection<MessageId> acked = new ArrayList<MessageId>();
+		Collection<MessageId> acked = new ArrayList<>();
 		for (MessageId m : a.getMessageIds()) {
 			if (db.containsVisibleMessage(txn, c, m)) {
 				db.raiseSeenFlag(txn, c, m);
@@ -770,6 +758,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		transaction.attach(new LocalAuthorRemovedEvent(a));
 	}
 
+	@Override
+	public void removeMessage(Transaction transaction, MessageId m)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		db.removeMessage(txn, m);
+	}
+
 	@Override
 	public void removeTransport(Transaction transaction, TransportId t)
 			throws DbException {
@@ -886,8 +884,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			Map<ContactId, TransportKeys> keys) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		Map<ContactId, TransportKeys> filtered =
+		Map<ContactId, TransportKeys> filtered = new HashMap<>();
-				new HashMap<ContactId, TransportKeys>();
 		for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
 			ContactId c = e.getKey();
 			TransportKeys k = e.getValue();

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseConstants.java

@@ -23,10 +23,4 @@ interface DatabaseConstants {
 	 */
 	String SCHEMA_VERSION_KEY = "schemaVersion";
 
-	/**
-	 * The {@link Settings} key under which the minimum supported database
-	 * schema version is stored.
-	 */
-	String MIN_SCHEMA_VERSION_KEY = "minSchemaVersion";
-
 }

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseExecutorModule.java

@@ -32,7 +32,7 @@ public class DatabaseExecutorModule {
 
 	public DatabaseExecutorModule() {
 		// Use an unbounded queue
-		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseModule.java

@@ -26,7 +26,7 @@ public class DatabaseModule {
 	@Singleton
 	DatabaseComponent provideDatabaseComponent(Database<Connection> db,
 			EventBus eventBus, ShutdownManager shutdown) {
-		return new DatabaseComponentImpl<Connection>(db, Connection.class,
+		return new DatabaseComponentImpl<>(db, Connection.class, eventBus,
-				eventBus, shutdown);
+				shutdown);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/db/JdbcDatabase.java

@@ -3,6 +3,8 @@ package org.briarproject.bramble.db;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DataTooNewException;
+import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbClosedException;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
@@ -47,6 +49,7 @@ import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
@@ -57,7 +60,6 @@ import static org.briarproject.bramble.api.sync.ValidationManager.State.INVALID;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.PENDING;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
 import static org.briarproject.bramble.db.DatabaseConstants.DB_SETTINGS_NAMESPACE;
-import static org.briarproject.bramble.db.DatabaseConstants.MIN_SCHEMA_VERSION_KEY;
 import static org.briarproject.bramble.db.DatabaseConstants.SCHEMA_VERSION_KEY;
 import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 
@@ -68,8 +70,8 @@ import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 @NotNullByDefault
 abstract class JdbcDatabase implements Database<Connection> {
 
-	private static final int SCHEMA_VERSION = 30;
+	// Package access for testing
-	private static final int MIN_SCHEMA_VERSION = 30;
+	static final int CODE_SCHEMA_VERSION = 31;
 
 	private static final String CREATE_SETTINGS =
 			"CREATE TABLE settings"
@@ -148,11 +150,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private static final String CREATE_MESSAGE_METADATA =
 			"CREATE TABLE messageMetadata"
 					+ " (messageId HASH NOT NULL,"
+					+ " groupId HASH NOT NULL," // Denormalised
+					+ " state INT NOT NULL," // Denormalised
 					+ " key VARCHAR NOT NULL,"
 					+ " value BINARY NOT NULL,"
 					+ " PRIMARY KEY (messageId, key),"
 					+ " FOREIGN KEY (messageId)"
 					+ " REFERENCES messages (messageId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
 					+ " ON DELETE CASCADE)";
 
 	private static final String CREATE_MESSAGE_DEPENDENCIES =
@@ -232,6 +239,18 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " REFERENCES transports (transportId)"
 					+ " ON DELETE CASCADE)";
 
+	private static final String INDEX_CONTACTS_BY_AUTHOR_ID =
+			"CREATE INDEX IF NOT EXISTS contactsByAuthorId"
+					+ " ON contacts (authorId)";
+
+	private static final String INDEX_GROUPS_BY_CLIENT_ID =
+			"CREATE INDEX IF NOT EXISTS groupsByClientId"
+					+ " ON groups (clientId)";
+
+	private static final String INDEX_MESSAGE_METADATA_BY_GROUP_ID_STATE =
+			"CREATE INDEX IF NOT EXISTS messageMetadataByGroupIdState"
+					+ " ON messageMetadata (groupId, state)";
+
 	private static final Logger LOG =
 			Logger.getLogger(JdbcDatabase.class.getName());
 
@@ -239,8 +258,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private final String hashType, binaryType, counterType, secretType;
 	private final Clock clock;
 
-	private final LinkedList<Connection> connections =
+	// Locking: connectionsLock
-			new LinkedList<Connection>(); // Locking: connectionsLock
+	private final LinkedList<Connection> connections = new LinkedList<>();
 
 	private int openConnections = 0; // Locking: connectionsLock
 	private boolean closed = false; // Locking: connectionsLock
@@ -267,15 +286,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 		} catch (ClassNotFoundException e) {
 			throw new DbException(e);
 		}
-		// Open the database and create the tables if necessary
+		// Open the database and create the tables and indexes if necessary
 		Connection txn = startTransaction();
 		try {
 			if (reopen) {
-				if (!checkSchemaVersion(txn)) throw new DbException();
+				checkSchemaVersion(txn);
 			} else {
 				createTables(txn);
-				storeSchemaVersion(txn);
+				storeSchemaVersion(txn, CODE_SCHEMA_VERSION);
 			}
+			createIndexes(txn);
 			commitTransaction(txn);
 		} catch (DbException e) {
 			abortTransaction(txn);
@@ -283,19 +303,49 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	private boolean checkSchemaVersion(Connection txn) throws DbException {
+	/**
+	 * Compares the schema version stored in the database with the schema
+	 * version used by the current code and applies any suitable migrations to
+	 * the data if necessary.
+	 *
+	 * @throws DataTooNewException if the data uses a newer schema than the
+	 * current code
+	 * @throws DataTooOldException if the data uses an older schema than the
+	 * current code and cannot be migrated
+	 */
+	private void checkSchemaVersion(Connection txn) throws DbException {
 		Settings s = getSettings(txn, DB_SETTINGS_NAMESPACE);
-		int schemaVersion = s.getInt(SCHEMA_VERSION_KEY, -1);
+		int dataSchemaVersion = s.getInt(SCHEMA_VERSION_KEY, -1);
-		if (schemaVersion == SCHEMA_VERSION) return true;
+		if (dataSchemaVersion == -1) throw new DbException();
-		if (schemaVersion < MIN_SCHEMA_VERSION) return false;
+		if (dataSchemaVersion == CODE_SCHEMA_VERSION) return;
-		int minSchemaVersion = s.getInt(MIN_SCHEMA_VERSION_KEY, -1);
+		if (CODE_SCHEMA_VERSION < dataSchemaVersion)
-		return SCHEMA_VERSION >= minSchemaVersion;
+			throw new DataTooNewException();
+		// Apply any suitable migrations in order
+		for (Migration<Connection> m : getMigrations()) {
+			int start = m.getStartVersion(), end = m.getEndVersion();
+			if (start == dataSchemaVersion) {
+				if (LOG.isLoggable(INFO))
+					LOG.info("Migrating from schema " + start + " to " + end);
+				// Apply the migration
+				m.migrate(txn);
+				// Store the new schema version
+				storeSchemaVersion(txn, end);
+				dataSchemaVersion = end;
+			}
+		}
+		if (dataSchemaVersion != CODE_SCHEMA_VERSION)
+			throw new DataTooOldException();
 	}
 
-	private void storeSchemaVersion(Connection txn) throws DbException {
+	// Package access for testing
+	List<Migration<Connection>> getMigrations() {
+		return Collections.singletonList(new Migration30_31());
+	}
+
+	private void storeSchemaVersion(Connection txn, int version)
+			throws DbException {
 		Settings s = new Settings();
-		s.putInt(SCHEMA_VERSION_KEY, SCHEMA_VERSION);
+		s.putInt(SCHEMA_VERSION_KEY, version);
-		s.putInt(MIN_SCHEMA_VERSION_KEY, MIN_SCHEMA_VERSION);
 		mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
 	}
 
@@ -340,6 +390,20 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	private void createIndexes(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.executeUpdate(INDEX_CONTACTS_BY_AUTHOR_ID);
+			s.executeUpdate(INDEX_GROUPS_BY_CLIENT_ID);
+			s.executeUpdate(INDEX_MESSAGE_METADATA_BY_GROUP_ID_STATE);
+			s.close();
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
 	private String insertTypeNames(String s) {
 		s = s.replaceAll("HASH", hashType);
 		s = s.replaceAll("BINARY", binaryType);
@@ -458,7 +522,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			// Create a contact row
 			String sql = "INSERT INTO contacts"
-					+ " (authorId, name, publicKey, localAuthorId, verified, active)"
+					+ " (authorId, name, publicKey, localAuthorId,"
+					+ " verified, active)"
 					+ " VALUES (?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, remote.getId().getBytes());
@@ -993,7 +1058,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " FROM contacts";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
-			List<Contact> contacts = new ArrayList<Contact>();
+			List<Contact> contacts = new ArrayList<>();
 			while (rs.next()) {
 				ContactId contactId = new ContactId(rs.getInt(1));
 				AuthorId authorId = new AuthorId(rs.getBytes(2));
@@ -1027,7 +1092,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, local.getBytes());
 			rs = ps.executeQuery();
-			List<ContactId> ids = new ArrayList<ContactId>();
+			List<ContactId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new ContactId(rs.getInt(1)));
 			rs.close();
 			ps.close();
@@ -1052,7 +1117,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, remote.getBytes());
 			rs = ps.executeQuery();
-			List<Contact> contacts = new ArrayList<Contact>();
+			List<Contact> contacts = new ArrayList<>();
 			while (rs.next()) {
 				ContactId c = new ContactId(rs.getInt(1));
 				String name = rs.getString(2);
@@ -1108,7 +1173,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, c.getString());
 			rs = ps.executeQuery();
-			List<Group> groups = new ArrayList<Group>();
+			List<Group> groups = new ArrayList<>();
 			while (rs.next()) {
 				GroupId id = new GroupId(rs.getBytes(1));
 				byte[] descriptor = rs.getBytes(2);
@@ -1161,7 +1226,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
-			List<ContactId> visible = new ArrayList<ContactId>();
+			List<ContactId> visible = new ArrayList<>();
 			while (rs.next()) visible.add(new ContactId(rs.getInt(1)));
 			rs.close();
 			ps.close();
@@ -1213,7 +1278,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " FROM localAuthors";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
-			List<LocalAuthor> authors = new ArrayList<LocalAuthor>();
+			List<LocalAuthor> authors = new ArrayList<>();
 			while (rs.next()) {
 				AuthorId authorId = new AuthorId(rs.getBytes(1));
 				String name = rs.getString(2);
@@ -1243,7 +1308,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1266,7 +1331,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, state.getValue());
 			ps.setBytes(2, g.getBytes());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1288,20 +1353,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			// Retrieve the message IDs for each query term and intersect
 			Set<MessageId> intersection = null;
-			String sql = "SELECT m.messageId"
+			String sql = "SELECT messageId FROM messageMetadata"
-					+ " FROM messages AS m"
+					+ " WHERE groupId = ? AND state = ?"
-					+ " JOIN messageMetadata AS md"
-					+ " ON m.messageId = md.messageId"
-					+ " WHERE state = ? AND groupId = ?"
 					+ " AND key = ? AND value = ?";
 			for (Entry<String, byte[]> e : query.entrySet()) {
 				ps = txn.prepareStatement(sql);
-				ps.setInt(1, DELIVERED.getValue());
+				ps.setBytes(1, g.getBytes());
-				ps.setBytes(2, g.getBytes());
+				ps.setInt(2, DELIVERED.getValue());
 				ps.setString(3, e.getKey());
 				ps.setBytes(4, e.getValue());
 				rs = ps.executeQuery();
-				Set<MessageId> ids = new HashSet<MessageId>();
+				Set<MessageId> ids = new HashSet<>();
 				while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 				rs.close();
 				ps.close();
@@ -1325,25 +1387,20 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT m.messageId, key, value"
+			String sql = "SELECT messageId, key, value"
-					+ " FROM messages AS m"
+					+ " FROM messageMetadata"
-					+ " JOIN messageMetadata AS md"
+					+ " WHERE groupId = ? AND state = ?";
-					+ " ON m.messageId = md.messageId"
-					+ " WHERE state = ? AND groupId = ?"
-					+ " ORDER BY m.messageId";
 			ps = txn.prepareStatement(sql);
-			ps.setInt(1, DELIVERED.getValue());
+			ps.setBytes(1, g.getBytes());
-			ps.setBytes(2, g.getBytes());
+			ps.setInt(2, DELIVERED.getValue());
 			rs = ps.executeQuery();
-			Map<MessageId, Metadata> all = new HashMap<MessageId, Metadata>();
+			Map<MessageId, Metadata> all = new HashMap<>();
-			Metadata metadata = null;
-			MessageId lastMessageId = null;
 			while (rs.next()) {
 				MessageId messageId = new MessageId(rs.getBytes(1));
-				if (lastMessageId == null || !messageId.equals(lastMessageId)) {
+				Metadata metadata = all.get(messageId);
+				if (metadata == null) {
 					metadata = new Metadata();
 					all.put(messageId, metadata);
-					lastMessageId = messageId;
 				}
 				metadata.put(rs.getString(2), rs.getBytes(3));
 			}
@@ -1364,8 +1421,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		Collection<MessageId> matches = getMessageIds(txn, g, query);
 		if (matches.isEmpty()) return Collections.emptyMap();
 		// Retrieve the metadata for each match
-		Map<MessageId, Metadata> all = new HashMap<MessageId, Metadata>(
+		Map<MessageId, Metadata> all = new HashMap<>(matches.size());
-				matches.size());
 		for (MessageId m : matches) all.put(m, getMessageMetadata(txn, m));
 		return all;
 	}
@@ -1399,10 +1455,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM messageMetadata AS md"
+			String sql = "SELECT key, value FROM messageMetadata"
-					+ " JOIN messages AS m"
+					+ " WHERE state = ? AND messageId = ?";
-					+ " ON m.messageId = md.messageId"
-					+ " WHERE m.state = ? AND md.messageId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, DELIVERED.getValue());
 			ps.setBytes(2, m.getBytes());
@@ -1425,11 +1479,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM messageMetadata AS md"
+			String sql = "SELECT key, value FROM messageMetadata"
-					+ " JOIN messages AS m"
+					+ " WHERE (state = ? OR state = ?)"
-					+ " ON m.messageId = md.messageId"
+					+ " AND messageId = ?";
-					+ " WHERE (m.state = ? OR m.state = ?)"
-					+ " AND md.messageId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, DELIVERED.getValue());
 			ps.setInt(2, PENDING.getValue());
@@ -1463,7 +1515,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setBytes(1, g.getBytes());
 			ps.setInt(2, c.getInt());
 			rs = ps.executeQuery();
-			List<MessageStatus> statuses = new ArrayList<MessageStatus>();
+			List<MessageStatus> statuses = new ArrayList<>();
 			while (rs.next()) {
 				MessageId messageId = new MessageId(rs.getBytes(1));
 				boolean sent = rs.getBoolean(2);
@@ -1522,7 +1574,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependencies = new HashMap<MessageId, State>();
+			Map<MessageId, State> dependencies = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependency = new MessageId(rs.getBytes(1));
 				State state = State.fromValue(rs.getInt(2));
@@ -1560,7 +1612,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependents = new HashMap<MessageId, State>();
+			Map<MessageId, State> dependents = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependent = new MessageId(rs.getBytes(1));
 				State state = State.fromValue(rs.getInt(2));
@@ -1612,7 +1664,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1648,7 +1700,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setLong(3, now);
 			ps.setInt(4, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1673,7 +1725,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1708,7 +1760,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
 			while (rs.next()) {
 				int length = rs.getInt(1);
@@ -1750,7 +1802,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, state.getValue());
 			ps.setString(2, c.getString());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1780,7 +1832,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, c.getString());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1839,7 +1891,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
 			while (rs.next()) {
 				int length = rs.getInt(1);
@@ -1893,7 +1945,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
-			List<IncomingKeys> inKeys = new ArrayList<IncomingKeys>();
+			List<IncomingKeys> inKeys = new ArrayList<>();
 			while (rs.next()) {
 				long rotationPeriod = rs.getLong(1);
 				SecretKey tagKey = new SecretKey(rs.getBytes(2));
@@ -1913,8 +1965,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
-			Map<ContactId, TransportKeys> keys =
+			Map<ContactId, TransportKeys> keys = new HashMap<>();
-					new HashMap<ContactId, TransportKeys>();
 			for (int i = 0; rs.next(); i++) {
 				// There should be three times as many incoming keys
 				if (inKeys.size() < (i + 1) * 3) throw new DbStateException();
@@ -2004,7 +2055,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int[] batchAffected = ps.executeBatch();
 			if (batchAffected.length != requested.size())
 				throw new DbStateException();
-			for (int rows: batchAffected) {
+			for (int rows : batchAffected) {
 				if (rows < 0) throw new DbStateException();
 				if (rows > 1) throw new DbStateException();
 			}
@@ -2018,25 +2069,92 @@ abstract class JdbcDatabase implements Database<Connection> {
 	@Override
 	public void mergeGroupMetadata(Connection txn, GroupId g, Metadata meta)
 			throws DbException {
-		mergeMetadata(txn, g.getBytes(), meta, "groupMetadata", "groupId");
+		PreparedStatement ps = null;
+		try {
+			Map<String, byte[]> added = removeOrUpdateMetadata(txn,
+					g.getBytes(), meta, "groupMetadata", "groupId");
+			if (added.isEmpty()) return;
+			// Insert any keys that don't already exist
+			String sql = "INSERT INTO groupMetadata (groupId, key, value)"
+					+ " VALUES (?, ?, ?)";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, g.getBytes());
+			for (Entry<String, byte[]> e : added.entrySet()) {
+				ps.setString(2, e.getKey());
+				ps.setBytes(3, e.getValue());
+				ps.addBatch();
+			}
+			int[] batchAffected = ps.executeBatch();
+			if (batchAffected.length != added.size())
+				throw new DbStateException();
+			for (int rows : batchAffected)
+				if (rows != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps);
+			throw new DbException(e);
+		}
 	}
 
 	@Override
-	public void mergeMessageMetadata(Connection txn, MessageId m, Metadata meta)
+	public void mergeMessageMetadata(Connection txn, MessageId m,
-			throws DbException {
+			Metadata meta) throws DbException {
-		mergeMetadata(txn, m.getBytes(), meta, "messageMetadata", "messageId");
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			Map<String, byte[]> added = removeOrUpdateMetadata(txn,
+					m.getBytes(), meta, "messageMetadata", "messageId");
+			if (added.isEmpty()) return;
+			// Get the group ID and message state for the denormalised columns
+			String sql = "SELECT groupId, state FROM messages"
+					+ " WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			GroupId g = new GroupId(rs.getBytes(1));
+			State state = State.fromValue(rs.getInt(2));
+			rs.close();
+			ps.close();
+			// Insert any keys that don't already exist
+			sql = "INSERT INTO messageMetadata"
+					+ " (messageId, groupId, state, key, value)"
+					+ " VALUES (?, ?, ?, ?, ?)";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setBytes(2, g.getBytes());
+			ps.setInt(3, state.getValue());
+			for (Entry<String, byte[]> e : added.entrySet()) {
+				ps.setString(4, e.getKey());
+				ps.setBytes(5, e.getValue());
+				ps.addBatch();
+			}
+			int[] batchAffected = ps.executeBatch();
+			if (batchAffected.length != added.size())
+				throw new DbStateException();
+			for (int rows : batchAffected)
+				if (rows != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
 	}
 
-	private void mergeMetadata(Connection txn, byte[] id, Metadata meta,
+	// Removes or updates any existing entries, returns any entries that
-			String tableName, String columnName) throws DbException {
+	// need to be added
+	private Map<String, byte[]> removeOrUpdateMetadata(Connection txn,
+			byte[] id, Metadata meta, String tableName, String columnName)
+			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			// Determine which keys are being removed
-			List<String> removed = new ArrayList<String>();
+			List<String> removed = new ArrayList<>();
-			Map<String, byte[]> retained = new HashMap<String, byte[]>();
+			Map<String, byte[]> notRemoved = new HashMap<>();
 			for (Entry<String, byte[]> e : meta.entrySet()) {
 				if (e.getValue() == REMOVE) removed.add(e.getKey());
-				else retained.put(e.getKey(), e.getValue());
+				else notRemoved.put(e.getKey(), e.getValue());
 			}
 			// Delete any keys that are being removed
 			if (!removed.isEmpty()) {
@@ -2057,45 +2175,33 @@ abstract class JdbcDatabase implements Database<Connection> {
 				}
 				ps.close();
 			}
-			if (retained.isEmpty()) return;
+			if (notRemoved.isEmpty()) return Collections.emptyMap();
 			// Update any keys that already exist
 			String sql = "UPDATE " + tableName + " SET value = ?"
 					+ " WHERE " + columnName + " = ? AND key = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(2, id);
-			for (Entry<String, byte[]> e : retained.entrySet()) {
+			for (Entry<String, byte[]> e : notRemoved.entrySet()) {
 				ps.setBytes(1, e.getValue());
 				ps.setString(3, e.getKey());
 				ps.addBatch();
 			}
 			int[] batchAffected = ps.executeBatch();
-			if (batchAffected.length != retained.size())
+			if (batchAffected.length != notRemoved.size())
 				throw new DbStateException();
 			for (int rows : batchAffected) {
 				if (rows < 0) throw new DbStateException();
 				if (rows > 1) throw new DbStateException();
 			}
-			// Insert any keys that don't already exist
-			sql = "INSERT INTO " + tableName
-					+ " (" + columnName + ", key, value)"
-					+ " VALUES (?, ?, ?)";
-			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, id);
-			int updateIndex = 0, inserted = 0;
-			for (Entry<String, byte[]> e : retained.entrySet()) {
-				if (batchAffected[updateIndex] == 0) {
-					ps.setString(2, e.getKey());
-					ps.setBytes(3, e.getValue());
-					ps.addBatch();
-					inserted++;
-				}
-				updateIndex++;
-			}
-			batchAffected = ps.executeBatch();
-			if (batchAffected.length != inserted) throw new DbStateException();
-			for (int rows : batchAffected)
-				if (rows != 1) throw new DbStateException();
 			ps.close();
+			// Are there any keys that don't already exist?
+			Map<String, byte[]> added = new HashMap<>();
+			int updateIndex = 0;
+			for (Entry<String, byte[]> e : notRemoved.entrySet()) {
+				if (batchAffected[updateIndex++] == 0)
+					added.put(e.getKey(), e.getValue());
+			}
+			return added;
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -2448,7 +2554,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void setMessageShared(Connection txn, MessageId m) throws DbException {
+	public void setMessageShared(Connection txn, MessageId m)
+			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE messages SET shared = TRUE"
@@ -2476,6 +2583,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int affected = ps.executeUpdate();
 			if (affected < 0 || affected > 1) throw new DbStateException();
 			ps.close();
+			// Update denormalised column in messageMetadata
+			sql = "UPDATE messageMetadata SET state = ? WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, state.getValue());
+			ps.setBytes(2, m.getBytes());
+			affected = ps.executeUpdate();
+			if (affected < 0) throw new DbStateException();
+			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);

bramble-core/src/main/java/org/briarproject/bramble/db/Migration.java

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+interface Migration<T> {
+
+	/**
+	 * Returns the schema version from which this migration starts.
+	 */
+	int getStartVersion();
+
+	/**
+	 * Returns the schema version at which this migration ends.
+	 */
+	int getEndVersion();
+
+	void migrate(T txn) throws DbException;
+}

bramble-core/src/main/java/org/briarproject/bramble/db/Migration30_31.java

@@ -0,0 +1,75 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+
+class Migration30_31 implements Migration<Connection> {
+
+	private static final Logger LOG =
+			Logger.getLogger(Migration30_31.class.getName());
+
+	@Override
+	public int getStartVersion() {
+		return 30;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 31;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			// Add groupId column
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ADD COLUMN groupId BINARY(32) AFTER messageId");
+			// Populate groupId column
+			s.execute("UPDATE messageMetadata AS mm SET groupId ="
+					+ " (SELECT groupId FROM messages AS m"
+					+ " WHERE mm.messageId = m.messageId)");
+			// Add not null constraint now column has been populated
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ALTER COLUMN groupId"
+					+ " SET NOT NULL");
+			// Add foreign key constraint
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ADD CONSTRAINT groupIdForeignKey"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
+					+ " ON DELETE CASCADE");
+			// Add state column
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ADD COLUMN state INT AFTER groupId");
+			// Populate state column
+			s.execute("UPDATE messageMetadata AS mm SET state ="
+					+ " (SELECT state FROM messages AS m"
+					+ " WHERE mm.messageId = m.messageId)");
+			// Add not null constraint now column has been populated
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ALTER COLUMN state"
+					+ " SET NOT NULL");
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
+	private void tryToClose(@Nullable Statement s) {
+		try {
+			if (s != null) s.close();
+		} catch (SQLException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/event/EventBusImpl.java

@@ -15,7 +15,7 @@ import javax.annotation.concurrent.ThreadSafe;
 class EventBusImpl implements EventBus {
 
 	private final Collection<EventListener> listeners =
-			new CopyOnWriteArrayList<EventListener>();
+			new CopyOnWriteArrayList<>();
 
 	@Override
 	public void addListener(EventListener l) {

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementConnector.java

@@ -50,10 +50,9 @@ class KeyAgreementConnector {
 	private final PluginManager pluginManager;
 	private final CompletionService<KeyAgreementConnection> connect;
 
-	private final List<KeyAgreementListener> listeners =
+	private final List<KeyAgreementListener> listeners = new ArrayList<>();
-			new ArrayList<KeyAgreementListener>();
 	private final List<Future<KeyAgreementConnection>> pending =
-			new ArrayList<Future<KeyAgreementConnection>>();
+			new ArrayList<>();
 
 	private volatile boolean connecting = false;
 	private volatile boolean alice = false;
@@ -65,8 +64,7 @@ class KeyAgreementConnector {
 		this.clock = clock;
 		this.crypto = crypto;
 		this.pluginManager = pluginManager;
-		connect = new ExecutorCompletionService<KeyAgreementConnection>(
+		connect = new ExecutorCompletionService<>(ioExecutor);
-				ioExecutor);
 	}
 
 	public Payload listen(KeyPair localKeyPair) {
@@ -75,8 +73,7 @@ class KeyAgreementConnector {
 		byte[] commitment = crypto.deriveKeyCommitment(
 				localKeyPair.getPublic().getEncoded());
 		// Start all listeners and collect their descriptors
-		List<TransportDescriptor> descriptors =
+		List<TransportDescriptor> descriptors = new ArrayList<>();
-				new ArrayList<TransportDescriptor>();
 		for (DuplexPlugin plugin : pluginManager.getKeyAgreementPlugins()) {
 			KeyAgreementListener l =
 					plugin.createKeyAgreementListener(commitment);
@@ -132,10 +129,7 @@ class KeyAgreementConnector {
 			LOG.info("Interrupted while waiting for connection");
 			Thread.currentThread().interrupt();
 			return null;
-		} catch (ExecutionException e) {
+		} catch (ExecutionException | IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return null;
-		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return null;
 		} finally {

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/PayloadParserImpl.java

@@ -51,8 +51,7 @@ class PayloadParserImpl implements PayloadParser {
 		byte[] commitment = payload.getRaw(1);
 		if (commitment.length != COMMIT_LENGTH) throw new FormatException();
 		// Remaining elements: transport descriptors
-		List<TransportDescriptor> recognised =
+		List<TransportDescriptor> recognised = new ArrayList<>();
-				new ArrayList<TransportDescriptor>();
 		for (int i = 2; i < payload.size(); i++) {
 			BdfList descriptor = payload.getList(i);
 			long transportId = descriptor.getLong(0);

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/LifecycleManagerImpl.java

@@ -63,9 +63,9 @@ class LifecycleManagerImpl implements LifecycleManager {
 		this.crypto = crypto;
 		this.authorFactory = authorFactory;
 		this.identityManager = identityManager;
-		services = new CopyOnWriteArrayList<Service>();
+		services = new CopyOnWriteArrayList<>();
-		clients = new CopyOnWriteArrayList<Client>();
+		clients = new CopyOnWriteArrayList<>();
-		executors = new CopyOnWriteArrayList<ExecutorService>();
+		executors = new CopyOnWriteArrayList<>();
 	}
 
 	@Override
@@ -88,7 +88,7 @@ class LifecycleManagerImpl implements LifecycleManager {
 		executors.add(e);
 	}
 
-	private LocalAuthor createLocalAuthor(final String nickname) {
+	private LocalAuthor createLocalAuthor(String nickname) {
 		long now = System.currentTimeMillis();
 		KeyPair keyPair = crypto.generateSignatureKeyPair();
 		byte[] publicKey = keyPair.getPublic().getEncoded();
@@ -203,9 +203,7 @@ class LifecycleManagerImpl implements LifecycleManager {
 			if (LOG.isLoggable(INFO))
 				LOG.info("Closing database took " + duration + " ms");
 			shutdownLatch.countDown();
-		} catch (DbException e) {
+		} catch (DbException | ServiceException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (ServiceException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		} finally {
 			startStopSemaphore.release();

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/LifecycleModule.java

@@ -37,7 +37,7 @@ public class LifecycleModule {
 
 	public LifecycleModule() {
 		// The thread pool is unbounded, so use direct handoff
-		BlockingQueue<Runnable> queue = new SynchronousQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new SynchronousQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/ShutdownManagerImpl.java

@@ -21,7 +21,7 @@ class ShutdownManagerImpl implements ShutdownManager {
 	private int nextHandle = 0;
 
 	ShutdownManagerImpl() {
-		hooks = new HashMap<Integer, Thread>();
+		hooks = new HashMap<>();
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/plugin/ConnectionManagerImpl.java

@@ -134,11 +134,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
+			} catch (IOException | DbException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;
@@ -249,11 +245,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
+			} catch (IOException | DbException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;
@@ -266,12 +258,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			contactId = ctx.getContactId();
 			connectionRegistry.registerConnection(contactId, transportId, true);
 			// Start the outgoing session on another thread
-			ioExecutor.execute(new Runnable() {
+			ioExecutor.execute(this::runOutgoingSession);
-				@Override
-				public void run() {
-					runOutgoingSession();
-				}
-			});
 			try {
 				// Create and run the incoming session
 				incomingSession = createIncomingSession(ctx, reader);
@@ -368,12 +355,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 				return;
 			}
 			// Start the incoming session on another thread
-			ioExecutor.execute(new Runnable() {
+			ioExecutor.execute(this::runIncomingSession);
-				@Override
-				public void run() {
-					runIncomingSession();
-				}
-			});
 			try {
 				// Create and run the outgoing session
 				outgoingSession = createDuplexOutgoingSession(ctx, writer);
@@ -391,11 +373,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
+			} catch (IOException | DbException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;

bramble-core/src/main/java/org/briarproject/bramble/plugin/ConnectionRegistryImpl.java

@@ -42,8 +42,8 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	@Inject
 	ConnectionRegistryImpl(EventBus eventBus) {
 		this.eventBus = eventBus;
-		connections = new HashMap<TransportId, Map<ContactId, Integer>>();
+		connections = new HashMap<>();
-		contactCounts = new HashMap<ContactId, Integer>();
+		contactCounts = new HashMap<>();
 	}
 
 	@Override
@@ -58,7 +58,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		try {
 			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) {
-				m = new HashMap<ContactId, Integer>();
+				m = new HashMap<>();
 				connections.put(t, m);
 			}
 			Integer count = m.get(c);
@@ -124,7 +124,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		try {
 			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) return Collections.emptyList();
-			List<ContactId> ids = new ArrayList<ContactId>(m.keySet());
+			List<ContactId> ids = new ArrayList<>(m.keySet());
 			if (LOG.isLoggable(INFO))
 				LOG.info(ids.size() + " contacts connected");
 			return ids;

bramble-core/src/main/java/org/briarproject/bramble/plugin/PluginManagerImpl.java

@@ -82,10 +82,10 @@ class PluginManagerImpl implements PluginManager, Service {
 		this.settingsManager = settingsManager;
 		this.transportPropertyManager = transportPropertyManager;
 		this.uiCallback = uiCallback;
-		plugins = new ConcurrentHashMap<TransportId, Plugin>();
+		plugins = new ConcurrentHashMap<>();
-		simplexPlugins = new CopyOnWriteArrayList<SimplexPlugin>();
+		simplexPlugins = new CopyOnWriteArrayList<>();
-		duplexPlugins = new CopyOnWriteArrayList<DuplexPlugin>();
+		duplexPlugins = new CopyOnWriteArrayList<>();
-		startLatches = new ConcurrentHashMap<TransportId, CountDownLatch>();
+		startLatches = new ConcurrentHashMap<>();
 	}
 
 	@Override
@@ -156,17 +156,17 @@ class PluginManagerImpl implements PluginManager, Service {
 
 	@Override
 	public Collection<SimplexPlugin> getSimplexPlugins() {
-		return new ArrayList<SimplexPlugin>(simplexPlugins);
+		return new ArrayList<>(simplexPlugins);
 	}
 
 	@Override
 	public Collection<DuplexPlugin> getDuplexPlugins() {
-		return new ArrayList<DuplexPlugin>(duplexPlugins);
+		return new ArrayList<>(duplexPlugins);
 	}
 
 	@Override
 	public Collection<DuplexPlugin> getKeyAgreementPlugins() {
-		List<DuplexPlugin> supported = new ArrayList<DuplexPlugin>();
+		List<DuplexPlugin> supported = new ArrayList<>();
 		for (DuplexPlugin d : duplexPlugins)
 			if (d.supportsKeyAgreement()) supported.add(d);
 		return supported;
@@ -283,6 +283,16 @@ class PluginManagerImpl implements PluginManager, Service {
 			}
 		}
 
+		@Override
+		public TransportProperties getRemoteProperties(ContactId c) {
+			try {
+				return transportPropertyManager.getRemoteProperties(c, id);
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				return new TransportProperties();
+			}
+		}
+
 		@Override
 		public void mergeSettings(Settings s) {
 			try {

bramble-core/src/main/java/org/briarproject/bramble/plugin/Poller.java

@@ -16,6 +16,7 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
 import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.system.Clock;
@@ -25,6 +26,7 @@ import java.security.SecureRandom;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -50,7 +52,7 @@ class Poller implements EventListener {
 	private final SecureRandom random;
 	private final Clock clock;
 	private final Lock lock;
-	private final Map<TransportId, PollTask> tasks; // Locking: lock
+	private final Map<TransportId, ScheduledPollTask> tasks; // Locking: lock
 
 	@Inject
 	Poller(@IoExecutor Executor ioExecutor,
@@ -66,7 +68,7 @@ class Poller implements EventListener {
 		this.random = random;
 		this.clock = clock;
 		lock = new ReentrantLock();
-		tasks = new HashMap<TransportId, PollTask>();
+		tasks = new HashMap<>();
 	}
 
 	@Override
@@ -93,6 +95,10 @@ class Poller implements EventListener {
 			TransportEnabledEvent t = (TransportEnabledEvent) e;
 			// Poll the newly enabled transport
 			pollNow(t.getTransportId());
+		} else if (e instanceof TransportDisabledEvent) {
+			TransportDisabledEvent t = (TransportDisabledEvent) e;
+			// Cancel polling for the disabled transport
+			cancel(t.getTransportId());
 		}
 	}
 
@@ -111,30 +117,24 @@ class Poller implements EventListener {
 			connectToContact(c, (DuplexPlugin) p);
 	}
 
-	private void connectToContact(final ContactId c, final SimplexPlugin p) {
+	private void connectToContact(ContactId c, SimplexPlugin p) {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			TransportId t = p.getId();
-			public void run() {
+			if (!connectionRegistry.isConnected(c, t)) {
-				TransportId t = p.getId();
+				TransportConnectionWriter w = p.createWriter(c);
-				if (!connectionRegistry.isConnected(c, t)) {
+				if (w != null)
-					TransportConnectionWriter w = p.createWriter(c);
+					connectionManager.manageOutgoingConnection(c, t, w);
-					if (w != null)
-						connectionManager.manageOutgoingConnection(c, t, w);
-				}
 			}
 		});
 	}
 
-	private void connectToContact(final ContactId c, final DuplexPlugin p) {
+	private void connectToContact(ContactId c, DuplexPlugin p) {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			TransportId t = p.getId();
-			public void run() {
+			if (!connectionRegistry.isConnected(c, t)) {
-				TransportId t = p.getId();
+				DuplexTransportConnection d = p.createConnection(c);
-				if (!connectionRegistry.isConnected(c, t)) {
+				if (d != null)
-					DuplexTransportConnection d = p.createConnection(c);
+					connectionManager.manageOutgoingConnection(c, t, d);
-					if (d != null)
-						connectionManager.manageOutgoingConnection(c, t, d);
-				}
 			}
 		});
 	}
@@ -157,29 +157,49 @@ class Poller implements EventListener {
 		TransportId t = p.getId();
 		lock.lock();
 		try {
-			PollTask scheduled = tasks.get(t);
+			ScheduledPollTask scheduled = tasks.get(t);
-			if (scheduled == null || due < scheduled.due) {
+			if (scheduled == null || due < scheduled.task.due) {
-				final PollTask task = new PollTask(p, due, randomiseNext);
+				// If a later task exists, cancel it. If it's already started
-				tasks.put(t, task);
+				// it will abort safely when it finds it's been replaced
-				scheduler.schedule(new Runnable() {
+				if (scheduled != null) scheduled.future.cancel(false);
-					@Override
+				PollTask task = new PollTask(p, due, randomiseNext);
-					public void run() {
+				Future future = scheduler.schedule(
-						ioExecutor.execute(task);
+						() -> ioExecutor.execute(task), delay, MILLISECONDS);
-					}
+				tasks.put(t, new ScheduledPollTask(task, future));
-				}, delay, MILLISECONDS);
 			}
 		} finally {
 			lock.unlock();
 		}
 	}
 
+	private void cancel(TransportId t) {
+		lock.lock();
+		try {
+			ScheduledPollTask scheduled = tasks.remove(t);
+			if (scheduled != null) scheduled.future.cancel(false);
+		} finally {
+			lock.unlock();
+		}
+	}
+
 	@IoExecutor
-	private void poll(final Plugin p) {
+	private void poll(Plugin p) {
 		TransportId t = p.getId();
 		if (LOG.isLoggable(INFO)) LOG.info("Polling plugin " + t);
 		p.poll(connectionRegistry.getConnectedContacts(t));
 	}
 
+	private class ScheduledPollTask {
+
+		private final PollTask task;
+		private final Future future;
+
+		private ScheduledPollTask(PollTask task, Future future) {
+			this.task = task;
+			this.future = future;
+		}
+	}
+
 	private class PollTask implements Runnable {
 
 		private final Plugin plugin;
@@ -198,7 +218,9 @@ class Poller implements EventListener {
 			lock.lock();
 			try {
 				TransportId t = plugin.getId();
-				if (tasks.get(t) != this) return; // Replaced by another task
+				ScheduledPollTask scheduled = tasks.get(t);
+				if (scheduled != null && scheduled.task != this)
+					return; // Replaced by another task
 				tasks.remove(t);
 			} finally {
 				lock.unlock();

bramble-core/src/main/java/org/briarproject/bramble/plugin/file/FilePlugin.java

@@ -108,7 +108,7 @@ abstract class FilePlugin implements SimplexPlugin {
 		}
 	}
 
-	protected void createReaderFromFile(final File f) {
+	protected void createReaderFromFile(File f) {
 		if (!running) return;
 		ioExecutor.execute(new ReaderCreator(f));
 	}

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/LanTcpPlugin.java

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.plugin.tcp;
 
 import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
@@ -24,7 +23,7 @@ import java.net.SocketAddress;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.LinkedList;
+import java.util.Comparator;
 import java.util.List;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
@@ -35,6 +34,7 @@ import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_LAN;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PREF_LAN_IP_PORTS;
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.PROP_IP_PORTS;
 import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubSocketAddress;
 
@@ -44,8 +44,10 @@ class LanTcpPlugin extends TcpPlugin {
 	private static final Logger LOG =
 			Logger.getLogger(LanTcpPlugin.class.getName());
 
+	private static final LanAddressComparator ADDRESS_COMPARATOR =
+			new LanAddressComparator();
+
 	private static final int MAX_ADDRESSES = 4;
-	private static final String PROP_IP_PORTS = "ipPorts";
 	private static final String SEPARATOR = ",";
 
 	LanTcpPlugin(Executor ioExecutor, Backoff backoff,
@@ -64,26 +66,25 @@ class LanTcpPlugin extends TcpPlugin {
 		TransportProperties p = callback.getLocalProperties();
 		String oldIpPorts = p.get(PROP_IP_PORTS);
 		List<InetSocketAddress> olds = parseSocketAddresses(oldIpPorts);
-		List<InetSocketAddress> locals = new LinkedList<InetSocketAddress>();
+		List<InetSocketAddress> locals = new ArrayList<>();
 		for (InetAddress local : getLocalIpAddresses()) {
 			if (isAcceptableAddress(local)) {
 				// If this is the old address, try to use the same port
 				for (InetSocketAddress old : olds) {
-					if (old.getAddress().equals(local)) {
+					if (old.getAddress().equals(local))
-						int port = old.getPort();
+						locals.add(new InetSocketAddress(local, old.getPort()));
-						locals.add(0, new InetSocketAddress(local, port));
-					}
 				}
 				locals.add(new InetSocketAddress(local, 0));
 			}
 		}
+		Collections.sort(locals, ADDRESS_COMPARATOR);
 		return locals;
 	}
 
 	private List<InetSocketAddress> parseSocketAddresses(String ipPorts) {
 		if (StringUtils.isNullOrEmpty(ipPorts)) return Collections.emptyList();
 		String[] split = ipPorts.split(SEPARATOR);
-		List<InetSocketAddress> addresses = new ArrayList<InetSocketAddress>();
+		List<InetSocketAddress> addresses = new ArrayList<>();
 		for (String ipPort : split) {
 			InetSocketAddress a = parseSocketAddress(ipPort);
 			if (a != null) addresses.add(a);
@@ -96,7 +97,7 @@ class LanTcpPlugin extends TcpPlugin {
 		String ipPort = getIpPortString(a);
 		// Get the list of recently used addresses
 		String setting = callback.getSettings().get(PREF_LAN_IP_PORTS);
-		List<String> recent = new ArrayList<String>();
+		List<String> recent = new ArrayList<>();
 		if (!StringUtils.isNullOrEmpty(setting))
 			Collections.addAll(recent, setting.split(SEPARATOR));
 		// Is the address already in the list?
@@ -112,7 +113,7 @@ class LanTcpPlugin extends TcpPlugin {
 				recent = recent.subList(0, MAX_ADDRESSES);
 			setting = StringUtils.join(recent, SEPARATOR);
 			// Update the list of addresses shared with contacts
-			List<String> shared = new ArrayList<String>(recent);
+			List<String> shared = new ArrayList<>(recent);
 			Collections.sort(shared);
 			String property = StringUtils.join(shared, SEPARATOR);
 			TransportProperties properties = new TransportProperties();
@@ -126,9 +127,8 @@ class LanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected List<InetSocketAddress> getRemoteSocketAddresses(ContactId c) {
+	protected List<InetSocketAddress> getRemoteSocketAddresses(
-		TransportProperties p = callback.getRemoteProperties().get(c);
+			TransportProperties p) {
-		if (p == null) return Collections.emptyList();
 		return parseSocketAddresses(p.get(PROP_IP_PORTS));
 	}
 
@@ -155,17 +155,39 @@ class LanTcpPlugin extends TcpPlugin {
 	// Package access for testing
 	boolean addressesAreOnSameLan(byte[] localIp, byte[] remoteIp) {
 		// 10.0.0.0/8
-		if (localIp[0] == 10) return remoteIp[0] == 10;
+		if (isPrefix10(localIp)) return isPrefix10(remoteIp);
 		// 172.16.0.0/12
-		if (localIp[0] == (byte) 172 && (localIp[1] & 0xF0) == 16)
+		if (isPrefix172(localIp)) return isPrefix172(remoteIp);
-			return remoteIp[0] == (byte) 172 && (remoteIp[1] & 0xF0) == 16;
 		// 192.168.0.0/16
-		if (localIp[0] == (byte) 192 && localIp[1] == (byte) 168)
+		if (isPrefix192(localIp)) return isPrefix192(remoteIp);
-			return remoteIp[0] == (byte) 192 && remoteIp[1] == (byte) 168;
 		// Unrecognised prefix - may be compatible
 		return true;
 	}
 
+	private static boolean isPrefix10(byte[] ipv4) {
+		return ipv4[0] == 10;
+	}
+
+	private static boolean isPrefix172(byte[] ipv4) {
+		return ipv4[0] == (byte) 172 && (ipv4[1] & 0xF0) == 16;
+	}
+
+	private static boolean isPrefix192(byte[] ipv4) {
+		return ipv4[0] == (byte) 192 && ipv4[1] == (byte) 168;
+	}
+
+	// Returns the prefix length for an RFC 1918 address, or 0 for any other
+	// address
+	private static int getRfc1918PrefixLength(InetAddress addr) {
+		if (!(addr instanceof Inet4Address)) return 0;
+		if (!addr.isSiteLocalAddress()) return 0;
+		byte[] ipv4 = addr.getAddress();
+		if (isPrefix10(ipv4)) return 8;
+		if (isPrefix172(ipv4)) return 12;
+		if (isPrefix192(ipv4)) return 16;
+		return 0;
+	}
+
 	@Override
 	public boolean supportsKeyAgreement() {
 		return true;
@@ -262,16 +284,12 @@ class LanTcpPlugin extends TcpPlugin {
 
 		@Override
 		public Callable<KeyAgreementConnection> listen() {
-			return new Callable<KeyAgreementConnection>() {
+			return () -> {
-				@Override
+				Socket s = ss.accept();
-				public KeyAgreementConnection call() throws IOException {
+				if (LOG.isLoggable(INFO))
-					Socket s = ss.accept();
+					LOG.info(ID.getString() + ": Incoming connection");
-					if (LOG.isLoggable(INFO))
+				return new KeyAgreementConnection(
-						LOG.info(ID.getString() + ": Incoming connection");
+						new TcpTransportConnection(LanTcpPlugin.this, s), ID);
-					return new KeyAgreementConnection(
-							new TcpTransportConnection(LanTcpPlugin.this, s),
-							ID);
-				}
 			};
 		}
 
@@ -284,4 +302,19 @@ class LanTcpPlugin extends TcpPlugin {
 			}
 		}
 	}
+
+	static class LanAddressComparator implements Comparator<InetSocketAddress> {
+
+		@Override
+		public int compare(InetSocketAddress a, InetSocketAddress b) {
+			// Prefer addresses with non-zero ports
+			int aPort = a.getPort(), bPort = b.getPort();
+			if (aPort > 0 && bPort == 0) return -1;
+			if (aPort == 0 && bPort > 0) return 1;
+			// Prefer addresses with longer RFC 1918 prefixes
+			int aPrefix = getRfc1918PrefixLength(a.getAddress());
+			int bPrefix = getRfc1918PrefixLength(b.getAddress());
+			return bPrefix - aPrefix;
+		}
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/PortMapperImpl.java

@@ -37,7 +37,7 @@ class PortMapperImpl implements PortMapper {
 	}
 
 	@Override
-	public MappingResult map(final int port) {
+	public MappingResult map(int port) {
 		if (!started.getAndSet(true)) start();
 		if (gateway == null) return null;
 		InetAddress internal = gateway.getLocalAddress();
@@ -50,12 +50,7 @@ class PortMapperImpl implements PortMapper {
 			succeeded = gateway.addPortMapping(port, port,
 					getHostAddress(internal), "TCP", "TCP");
 			if (succeeded) {
-				shutdownManager.addShutdownHook(new Runnable() {
+				shutdownManager.addShutdownHook(() -> deleteMapping(port));
-					@Override
-					public void run() {
-						deleteMapping(port);
-					}
-				});
 			}
 			String externalString = gateway.getExternalIPAddress();
 			if (LOG.isLoggable(INFO))
@@ -63,9 +58,7 @@ class PortMapperImpl implements PortMapper {
 						"External address " + scrubInetAddress(externalString));
 			if (externalString != null)
 				external = InetAddress.getByName(externalString);
-		} catch (IOException e) {
+		} catch (IOException | SAXException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 		return new MappingResult(internal, external, port, succeeded);
@@ -82,11 +75,7 @@ class PortMapperImpl implements PortMapper {
 		GatewayDiscover d = new GatewayDiscover();
 		try {
 			d.discover();
-		} catch (IOException e) {
+		} catch (IOException | SAXException | ParserConfigurationException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (ParserConfigurationException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 		gateway = d.getValidGateway();
@@ -97,9 +86,7 @@ class PortMapperImpl implements PortMapper {
 			gateway.deletePortMapping(port, "TCP");
 			if (LOG.isLoggable(INFO))
 				LOG.info("Deleted mapping for port " + port);
-		} catch (IOException e) {
+		} catch (IOException | SAXException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 	}

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/TcpPlugin.java

@@ -9,6 +9,7 @@ import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.util.StringUtils;
 
 import java.io.IOException;
@@ -24,6 +25,8 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
@@ -66,11 +69,11 @@ abstract class TcpPlugin implements DuplexPlugin {
 	protected abstract void setLocalSocketAddress(InetSocketAddress a);
 
 	/**
-	 * Returns zero or more socket addresses for connecting to the given
+	 * Returns zero or more socket addresses for connecting to a contact with
-	 * contact.
+	 * the given transport properties.
 	 */
 	protected abstract List<InetSocketAddress> getRemoteSocketAddresses(
-			ContactId c);
+			TransportProperties p);
 
 	/**
 	 * Returns true if connections to the given address can be attempted.
@@ -107,41 +110,37 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	protected void bind() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!running) return;
-			public void run() {
+			ServerSocket ss = null;
-				if (!running) return;
+			for (InetSocketAddress addr : getLocalSocketAddresses()) {
-				ServerSocket ss = null;
+				try {
-				for (InetSocketAddress addr : getLocalSocketAddresses()) {
+					ss = new ServerSocket();
-					try {
+					ss.bind(addr);
-						ss = new ServerSocket();
+					break;
-						ss.bind(addr);
+				} catch (IOException e) {
-						break;
+					if (LOG.isLoggable(INFO))
-					} catch (IOException e) {
+						LOG.info("Failed to bind " + scrubSocketAddress(addr));
-						if (LOG.isLoggable(INFO))
-							LOG.info("Failed to bind " +
-									scrubSocketAddress(addr));
-						tryToClose(ss);
-					}
-				}
-				if (ss == null || !ss.isBound()) {
-					LOG.info("Could not bind server socket");
-					return;
-				}
-				if (!running) {
 					tryToClose(ss);
-					return;
 				}
-				socket = ss;
-				backoff.reset();
-				InetSocketAddress local =
-						(InetSocketAddress) ss.getLocalSocketAddress();
-				setLocalSocketAddress(local);
-				if (LOG.isLoggable(INFO))
-					LOG.info("Listening on " + scrubSocketAddress(local));
-				callback.transportEnabled();
-				acceptContactConnections();
 			}
+			if (ss == null || !ss.isBound()) {
+				LOG.info("Could not bind server socket");
+				return;
+			}
+			if (!running) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			backoff.reset();
+			InetSocketAddress local =
+					(InetSocketAddress) ss.getLocalSocketAddress();
+			setLocalSocketAddress(local);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Listening on " + scrubSocketAddress(local));
+			callback.transportEnabled();
+			acceptContactConnections();
 		});
 	}
 
@@ -207,20 +206,21 @@ abstract class TcpPlugin implements DuplexPlugin {
 	public void poll(Collection<ContactId> connected) {
 		if (!isRunning()) return;
 		backoff.increment();
-		// TODO: Pass properties to connectAndCallBack()
+		Map<ContactId, TransportProperties> remote =
-		for (ContactId c : callback.getRemoteProperties().keySet())
+				callback.getRemoteProperties();
-			if (!connected.contains(c)) connectAndCallBack(c);
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (!connected.contains(c)) connectAndCallBack(c, e.getValue());
+		}
 	}
 
-	private void connectAndCallBack(final ContactId c) {
+	private void connectAndCallBack(ContactId c, TransportProperties p) {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!isRunning()) return;
-			public void run() {
+			DuplexTransportConnection d = createConnection(p);
-				DuplexTransportConnection d = createConnection(c);
+			if (d != null) {
-				if (d != null) {
+				backoff.reset();
-					backoff.reset();
+				callback.outgoingConnectionCreated(c, d);
-					callback.outgoingConnectionCreated(c, d);
-				}
 			}
 		});
 	}
@@ -228,7 +228,12 @@ abstract class TcpPlugin implements DuplexPlugin {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
-		for (InetSocketAddress remote : getRemoteSocketAddresses(c)) {
+		return createConnection(callback.getRemoteProperties(c));
+	}
+
+	@Nullable
+	private DuplexTransportConnection createConnection(TransportProperties p) {
+		for (InetSocketAddress remote : getRemoteSocketAddresses(p)) {
 			if (!isConnectable(remote)) {
 				if (LOG.isLoggable(INFO)) {
 					SocketAddress local = socket.getLocalSocketAddress();
@@ -304,7 +309,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return Collections.emptyList();
 		}
-		List<InetAddress> addrs = new ArrayList<InetAddress>();
+		List<InetAddress> addrs = new ArrayList<>();
 		for (NetworkInterface iface : ifaces)
 			addrs.addAll(Collections.list(iface.getInetAddresses()));
 		return addrs;

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/WanTcpPlugin.java

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.plugin.tcp;
 
-import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -44,7 +43,7 @@ class WanTcpPlugin extends TcpPlugin {
 		// Use the same address and port as last time if available
 		TransportProperties p = callback.getLocalProperties();
 		InetSocketAddress old = parseSocketAddress(p.get(PROP_IP_PORT));
-		List<InetSocketAddress> addrs = new LinkedList<InetSocketAddress>();
+		List<InetSocketAddress> addrs = new LinkedList<>();
 		for (InetAddress a : getLocalIpAddresses()) {
 			if (isAcceptableAddress(a)) {
 				// If this is the old address, try to use the same port
@@ -78,9 +77,8 @@ class WanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected List<InetSocketAddress> getRemoteSocketAddresses(ContactId c) {
+	protected List<InetSocketAddress> getRemoteSocketAddresses(
-		TransportProperties p = callback.getRemoteProperties().get(c);
+			TransportProperties p) {
-		if (p == null) return Collections.emptyList();
 		InetSocketAddress parsed = parseSocketAddress(p.get(PROP_IP_PORT));
 		if (parsed == null) return Collections.emptyList();
 		return Collections.singletonList(parsed);

bramble-core/src/main/java/org/briarproject/bramble/properties/PropertiesModule.java

@@ -40,9 +40,12 @@ public class PropertiesModule {
 	@Provides
 	@Singleton
 	TransportPropertyManager getTransportPropertyManager(
-			LifecycleManager lifecycleManager, ContactManager contactManager,
+			LifecycleManager lifecycleManager,
+			ValidationManager validationManager, ContactManager contactManager,
 			TransportPropertyManagerImpl transportPropertyManager) {
 		lifecycleManager.registerClient(transportPropertyManager);
+		validationManager.registerIncomingMessageHook(CLIENT_ID,
+				transportPropertyManager);
 		contactManager.registerAddContactHook(transportPropertyManager);
 		contactManager.registerRemoveContactHook(transportPropertyManager);
 		return transportPropertyManager;

bramble-core/src/main/java/org/briarproject/bramble/properties/TransportPropertyManagerImpl.java

@@ -9,8 +9,10 @@ import org.briarproject.bramble.api.contact.ContactManager.AddContactHook;
 import org.briarproject.bramble.api.contact.ContactManager.RemoveContactHook;
 import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataParser;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -19,8 +21,10 @@ import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.ValidationManager.IncomingMessageHook;
 import org.briarproject.bramble.api.system.Clock;
 
 import java.util.HashMap;
@@ -36,20 +40,22 @@ import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 @Immutable
 @NotNullByDefault
 class TransportPropertyManagerImpl implements TransportPropertyManager,
-		Client, AddContactHook, RemoveContactHook {
+		Client, AddContactHook, RemoveContactHook, IncomingMessageHook {
 
 	private final DatabaseComponent db;
 	private final ClientHelper clientHelper;
+	private final MetadataParser metadataParser;
 	private final ContactGroupFactory contactGroupFactory;
 	private final Clock clock;
 	private final Group localGroup;
 
 	@Inject
 	TransportPropertyManagerImpl(DatabaseComponent db,
-			ClientHelper clientHelper, ContactGroupFactory contactGroupFactory,
+			ClientHelper clientHelper, MetadataParser metadataParser,
-			Clock clock) {
+			ContactGroupFactory contactGroupFactory, Clock clock) {
 		this.db = db;
 		this.clientHelper = clientHelper;
+		this.metadataParser = metadataParser;
 		this.contactGroupFactory = contactGroupFactory;
 		this.clock = clock;
 		localGroup = contactGroupFactory.createLocalGroup(CLIENT_ID);
@@ -57,6 +63,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 
 	@Override
 	public void createLocalState(Transaction txn) throws DbException {
+		if (db.containsGroup(txn, localGroup.getId())) return;
 		db.addGroup(txn, localGroup);
 		// Ensure we've set things up for any pre-existing contacts
 		for (Contact c : db.getContacts(txn)) addingContact(txn, c);
@@ -84,6 +91,31 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		db.removeGroup(txn, getContactGroup(c));
 	}
 
+	@Override
+	public boolean incomingMessage(Transaction txn, Message m, Metadata meta)
+			throws DbException, InvalidMessageException {
+		try {
+			// Find the latest update for this transport, if any
+			BdfDictionary d = metadataParser.parse(meta);
+			TransportId t = new TransportId(d.getString("transportId"));
+			LatestUpdate latest = findLatest(txn, m.getGroupId(), t, false);
+			if (latest != null) {
+				if (d.getLong("version") > latest.version) {
+					// This update is newer - delete the previous update
+					db.deleteMessage(txn, latest.messageId);
+					db.deleteMessageMetadata(txn, latest.messageId);
+				} else {
+					// We've already received a newer update - delete this one
+					db.deleteMessage(txn, m.getId());
+					db.deleteMessageMetadata(txn, m.getId());
+				}
+			}
+		} catch (FormatException e) {
+			throw new InvalidMessageException(e);
+		}
+		return false;
+	}
+
 	@Override
 	public void addRemoteProperties(Transaction txn, ContactId c,
 			Map<TransportId, TransportProperties> props) throws DbException {
@@ -98,7 +130,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public Map<TransportId, TransportProperties> getLocalProperties()
 			throws DbException {
 		Map<TransportId, TransportProperties> local;
-		Transaction txn = db.startTransaction(true);
+		// TODO: Transaction can be read-only when code is simplified
+		Transaction txn = db.startTransaction(false);
 		try {
 			local = getLocalProperties(txn);
 			db.commitTransaction(txn);
@@ -112,11 +145,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public Map<TransportId, TransportProperties> getLocalProperties(
 			Transaction txn) throws DbException {
 		try {
-			Map<TransportId, TransportProperties> local =
+			Map<TransportId, TransportProperties> local = new HashMap<>();
-					new HashMap<TransportId, TransportProperties>();
 			// Find the latest local update for each transport
-			Map<TransportId, LatestUpdate> latest = findLatest(txn,
+			Map<TransportId, LatestUpdate> latest = findLatestLocal(txn);
-					localGroup.getId(), true);
 			// Retrieve and parse the latest local properties
 			for (Entry<TransportId, LatestUpdate> e : latest.entrySet()) {
 				BdfList message = clientHelper.getMessageAsList(txn,
@@ -135,7 +166,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 			throws DbException {
 		try {
 			TransportProperties p = null;
-			Transaction txn = db.startTransaction(true);
+			// TODO: Transaction can be read-only when code is simplified
+			Transaction txn = db.startTransaction(false);
 			try {
 				// Find the latest local update
 				LatestUpdate latest = findLatest(txn, localGroup.getId(), t,
@@ -160,35 +192,53 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public Map<ContactId, TransportProperties> getRemoteProperties(
 			TransportId t) throws DbException {
+		Map<ContactId, TransportProperties> remote = new HashMap<>();
+		// TODO: Transaction can be read-only when code is simplified
+		Transaction txn = db.startTransaction(false);
 		try {
-			Map<ContactId, TransportProperties> remote =
+			for (Contact c : db.getContacts(txn))
-					new HashMap<ContactId, TransportProperties>();
+				remote.put(c.getId(), getRemoteProperties(txn, c, t));
-			Transaction txn = db.startTransaction(true);
+			db.commitTransaction(txn);
-			try {
+		} finally {
-				for (Contact c : db.getContacts(txn)) {
+			db.endTransaction(txn);
-					// Don't return properties for inactive contacts
+		}
-					if (!c.isActive()) continue;
+		return remote;
-					Group g = getContactGroup(c);
+	}
-					// Find the latest remote update
+
-					LatestUpdate latest = findLatest(txn, g.getId(), t, false);
+	private TransportProperties getRemoteProperties(Transaction txn, Contact c,
-					if (latest != null) {
+			TransportId t) throws DbException {
-						// Retrieve and parse the latest remote properties
+		// Don't return properties for inactive contacts
-						BdfList message = clientHelper.getMessageAsList(txn,
+		if (!c.isActive()) return new TransportProperties();
-								latest.messageId);
+		Group g = getContactGroup(c);
-						if (message == null) throw new DbException();
+		try {
-						remote.put(c.getId(), parseProperties(message));
+			// Find the latest remote update
-					}
+			LatestUpdate latest = findLatest(txn, g.getId(), t, false);
-				}
+			if (latest == null) return new TransportProperties();
-				db.commitTransaction(txn);
+			// Retrieve and parse the latest remote properties
-			} finally {
+			BdfList message =
-				db.endTransaction(txn);
+					clientHelper.getMessageAsList(txn, latest.messageId);
-			}
+			if (message == null) throw new DbException();
-			return remote;
+			return parseProperties(message);
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}
 	}
 
+	@Override
+	public TransportProperties getRemoteProperties(ContactId c, TransportId t)
+			throws DbException {
+		TransportProperties p;
+		// TODO: Transaction can be read-only when code is simplified
+		Transaction txn = db.startTransaction(false);
+		try {
+			p = getRemoteProperties(txn, db.getContact(txn, c), t);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return p;
+	}
+
 	@Override
 	public void mergeLocalProperties(TransportId t, TransportProperties p)
 			throws DbException {
@@ -217,6 +267,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 					long version = latest == null ? 1 : latest.version + 1;
 					storeMessage(txn, localGroup.getId(), t, merged, version,
 							true, false);
+					// Delete the previous update, if any
+					if (latest != null)
+						db.removeMessage(txn, latest.messageId);
 					// Store the merged properties in each contact's group
 					for (Contact c : db.getContacts(txn)) {
 						Group g = getContactGroup(c);
@@ -224,6 +277,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 						version = latest == null ? 1 : latest.version + 1;
 						storeMessage(txn, g.getId(), t, merged, version,
 								true, true);
+						// Delete the previous update, if any
+						if (latest != null)
+							db.removeMessage(txn, latest.messageId);
 					}
 				}
 				db.commitTransaction(txn);
@@ -261,20 +317,26 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		return BdfList.of(t.getString(), version, p);
 	}
 
-	private Map<TransportId, LatestUpdate> findLatest(Transaction txn,
+	private Map<TransportId, LatestUpdate> findLatestLocal(Transaction txn)
-			GroupId g, boolean local) throws DbException, FormatException {
+			throws DbException, FormatException {
-		Map<TransportId, LatestUpdate> latestUpdates =
+		// TODO: This can be simplified before 1.0
-				new HashMap<TransportId, LatestUpdate>();
+		Map<TransportId, LatestUpdate> latestUpdates = new HashMap<>();
-		Map<MessageId, BdfDictionary> metadata =
+		Map<MessageId, BdfDictionary> metadata = clientHelper
-				clientHelper.getMessageMetadataAsDictionary(txn, g);
+				.getMessageMetadataAsDictionary(txn, localGroup.getId());
 		for (Entry<MessageId, BdfDictionary> e : metadata.entrySet()) {
 			BdfDictionary meta = e.getValue();
-			if (meta.getBoolean("local") == local) {
+			TransportId t = new TransportId(meta.getString("transportId"));
-				TransportId t = new TransportId(meta.getString("transportId"));
+			long version = meta.getLong("version");
-				long version = meta.getLong("version");
+			LatestUpdate latest = latestUpdates.get(t);
-				LatestUpdate latest = latestUpdates.get(t);
+			if (latest == null) {
-				if (latest == null || version > latest.version)
+				latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
-					latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
+			} else if (version > latest.version) {
+				// This update is newer - delete the previous one
+				db.removeMessage(txn, latest.messageId);
+				latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
+			} else {
+				// We've already found a newer update - delete this one
+				db.removeMessage(txn, e.getKey());
 			}
 		}
 		return latestUpdates;
@@ -283,6 +345,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Nullable
 	private LatestUpdate findLatest(Transaction txn, GroupId g, TransportId t,
 			boolean local) throws DbException, FormatException {
+		// TODO: This can be simplified before 1.0
 		LatestUpdate latest = null;
 		Map<MessageId, BdfDictionary> metadata =
 				clientHelper.getMessageMetadataAsDictionary(txn, g);
@@ -291,8 +354,26 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 			if (meta.getString("transportId").equals(t.getString())
 					&& meta.getBoolean("local") == local) {
 				long version = meta.getLong("version");
-				if (latest == null || version > latest.version)
+				if (latest == null) {
 					latest = new LatestUpdate(e.getKey(), version);
+				} else if (version > latest.version) {
+					// This update is newer - delete the previous one
+					if (local) {
+						db.removeMessage(txn, latest.messageId);
+					} else {
+						db.deleteMessage(txn, latest.messageId);
+						db.deleteMessageMetadata(txn, latest.messageId);
+					}
+					latest = new LatestUpdate(e.getKey(), version);
+				} else {
+					// We've already found a newer update - delete this one
+					if (local) {
+						db.removeMessage(txn, e.getKey());
+					} else {
+						db.deleteMessage(txn, e.getKey());
+						db.deleteMessageMetadata(txn, e.getKey());
+					}
+				}
 			}
 		}
 		return latest;

bramble-core/src/main/java/org/briarproject/bramble/reliability/Receiver.java

@@ -41,7 +41,7 @@ class Receiver implements ReadHandler {
 	Receiver(Clock clock, Sender sender) {
 		this.sender = sender;
 		this.clock = clock;
-		dataFrames = new TreeSet<Data>(new SequenceNumberComparator());
+		dataFrames = new TreeSet<>(new SequenceNumberComparator());
 	}
 
 	Data read() throws IOException, InterruptedException {

bramble-core/src/main/java/org/briarproject/bramble/reliability/ReliabilityLayerImpl.java

@@ -42,48 +42,44 @@ class ReliabilityLayerImpl implements ReliabilityLayer, WriteHandler {
 		this.executor = executor;
 		this.clock = clock;
 		this.writeHandler = writeHandler;
-		writes = new LinkedBlockingQueue<byte[]>();
+		writes = new LinkedBlockingQueue<>();
 	}
 
 	@Override
 	public void start() {
 		SlipEncoder encoder = new SlipEncoder(this);
-		final Sender sender = new Sender(clock, encoder);
+		Sender sender = new Sender(clock, encoder);
 		receiver = new Receiver(clock, sender);
 		decoder = new SlipDecoder(receiver, Data.MAX_LENGTH);
 		inputStream = new ReceiverInputStream(receiver);
 		outputStream = new SenderOutputStream(sender);
 		running = true;
-		executor.execute(new Runnable() {
+		executor.execute(() -> {
-			@Override
+			long now = clock.currentTimeMillis();
-			public void run() {
+			long next = now + TICK_INTERVAL;
-				long now = clock.currentTimeMillis();
+			try {
-				long next = now + TICK_INTERVAL;
+				while (running) {
-				try {
+					byte[] b = null;
-					while (running) {
+					while (now < next && b == null) {
-						byte[] b = null;
+						b = writes.poll(next - now, MILLISECONDS);
-						while (now < next && b == null) {
+						if (!running) return;
-							b = writes.poll(next - now, MILLISECONDS);
+						now = clock.currentTimeMillis();
-							if (!running) return;
+					}
-							now = clock.currentTimeMillis();
+					if (b == null) {
-						}
+						sender.tick();
-						if (b == null) {
+						while (next <= now) next += TICK_INTERVAL;
-							sender.tick();
+					} else {
-							while (next <= now) next += TICK_INTERVAL;
+						if (b.length == 0) return; // Poison pill
-						} else {
+						writeHandler.handleWrite(b);
-							if (b.length == 0) return; // Poison pill
-							writeHandler.handleWrite(b);
-						}
 					}
-				} catch (InterruptedException e) {
-					LOG.warning("Interrupted while waiting to write");
-					Thread.currentThread().interrupt();
-					running = false;
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					running = false;
 				}
+			} catch (InterruptedException e) {
+				LOG.warning("Interrupted while waiting to write");
+				Thread.currentThread().interrupt();
+				running = false;
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				running = false;
 			}
 		});
 	}

bramble-core/src/main/java/org/briarproject/bramble/reliability/Sender.java

@@ -46,7 +46,7 @@ class Sender {
 	Sender(Clock clock, WriteHandler writeHandler) {
 		this.clock = clock;
 		this.writeHandler = writeHandler;
-		outstanding = new LinkedList<Outstanding>();
+		outstanding = new LinkedList<>();
 	}
 
 	void sendAck(long sequenceNumber, int windowSize) throws IOException {
@@ -136,7 +136,7 @@ class Sender {
 					if (now - o.lastTransmitted > rto) {
 						it.remove();
 						if (retransmit == null)
-							retransmit = new ArrayList<Outstanding>();
+							retransmit = new ArrayList<>();
 						retransmit.add(o);
 						// Update the retransmission timeout
 						rto <<= 1;

bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java

@@ -29,6 +29,7 @@ import java.util.Collection;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.Executor;
 import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.ThreadSafe;
@@ -54,12 +55,8 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(DuplexOutgoingSession.class.getName());
 
-	private static final ThrowingRunnable<IOException> CLOSE =
+	private static final ThrowingRunnable<IOException> CLOSE = () -> {
-			new ThrowingRunnable<IOException>() {
+	};
-				@Override
-				public void run() {
-				}
-			};
 
 	private final DatabaseComponent db;
 	private final Executor dbExecutor;
@@ -70,6 +67,12 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	private final RecordWriter recordWriter;
 	private final BlockingQueue<ThrowingRunnable<IOException>> writerTasks;
 
+	private final AtomicBoolean generateAckQueued = new AtomicBoolean(false);
+	private final AtomicBoolean generateBatchQueued = new AtomicBoolean(false);
+	private final AtomicBoolean generateOfferQueued = new AtomicBoolean(false);
+	private final AtomicBoolean generateRequestQueued =
+			new AtomicBoolean(false);
+
 	private volatile boolean interrupted = false;
 
 	DuplexOutgoingSession(DatabaseComponent db, Executor dbExecutor,
@@ -83,7 +86,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		this.maxLatency = maxLatency;
 		this.maxIdleTime = maxIdleTime;
 		this.recordWriter = recordWriter;
-		writerTasks = new LinkedBlockingQueue<ThrowingRunnable<IOException>>();
+		writerTasks = new LinkedBlockingQueue<>();
 	}
 
 	@IoExecutor
@@ -92,10 +95,10 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		eventBus.addListener(this);
 		try {
 			// Start a query for each type of record
-			dbExecutor.execute(new GenerateAck());
+			generateAck();
-			dbExecutor.execute(new GenerateBatch());
+			generateBatch();
-			dbExecutor.execute(new GenerateOffer());
+			generateOffer();
-			dbExecutor.execute(new GenerateRequest());
+			generateRequest();
 			long now = clock.currentTimeMillis();
 			long nextKeepalive = now + maxIdleTime;
 			long nextRetxQuery = now + RETX_QUERY_INTERVAL;
@@ -120,8 +123,8 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 						now = clock.currentTimeMillis();
 						if (now >= nextRetxQuery) {
 							// Check for retransmittable records
-							dbExecutor.execute(new GenerateBatch());
+							generateBatch();
-							dbExecutor.execute(new GenerateOffer());
+							generateOffer();
 							nextRetxQuery = now + RETX_QUERY_INTERVAL;
 						}
 						if (now >= nextKeepalive) {
@@ -147,6 +150,26 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		}
 	}
 
+	private void generateAck() {
+		if (generateAckQueued.compareAndSet(false, true))
+			dbExecutor.execute(new GenerateAck());
+	}
+
+	private void generateBatch() {
+		if (generateBatchQueued.compareAndSet(false, true))
+			dbExecutor.execute(new GenerateBatch());
+	}
+
+	private void generateOffer() {
+		if (generateOfferQueued.compareAndSet(false, true))
+			dbExecutor.execute(new GenerateOffer());
+	}
+
+	private void generateRequest() {
+		if (generateRequestQueued.compareAndSet(false, true))
+			dbExecutor.execute(new GenerateRequest());
+	}
+
 	@Override
 	public void interrupt() {
 		interrupted = true;
@@ -159,20 +182,20 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			ContactRemovedEvent c = (ContactRemovedEvent) e;
 			if (c.getContactId().equals(contactId)) interrupt();
 		} else if (e instanceof MessageSharedEvent) {
-			dbExecutor.execute(new GenerateOffer());
+			generateOffer();
 		} else if (e instanceof GroupVisibilityUpdatedEvent) {
 			GroupVisibilityUpdatedEvent g = (GroupVisibilityUpdatedEvent) e;
 			if (g.getAffectedContacts().contains(contactId))
-				dbExecutor.execute(new GenerateOffer());
+				generateOffer();
 		} else if (e instanceof MessageRequestedEvent) {
 			if (((MessageRequestedEvent) e).getContactId().equals(contactId))
-				dbExecutor.execute(new GenerateBatch());
+				generateBatch();
 		} else if (e instanceof MessageToAckEvent) {
 			if (((MessageToAckEvent) e).getContactId().equals(contactId))
-				dbExecutor.execute(new GenerateAck());
+				generateAck();
 		} else if (e instanceof MessageToRequestEvent) {
 			if (((MessageToRequestEvent) e).getContactId().equals(contactId))
-				dbExecutor.execute(new GenerateRequest());
+				generateRequest();
 		} else if (e instanceof ShutdownEvent) {
 			interrupt();
 		}
@@ -184,6 +207,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
+			if (!generateAckQueued.getAndSet(false)) throw new AssertionError();
 			try {
 				Ack a;
 				Transaction txn = db.startTransaction(false);
@@ -217,7 +241,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			recordWriter.writeAck(ack);
 			LOG.info("Sent ack");
-			dbExecutor.execute(new GenerateAck());
+			generateAck();
 		}
 	}
 
@@ -227,6 +251,8 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
+			if (!generateBatchQueued.getAndSet(false))
+				throw new AssertionError();
 			try {
 				Collection<byte[]> b;
 				Transaction txn = db.startTransaction(false);
@@ -261,7 +287,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			for (byte[] raw : batch) recordWriter.writeMessage(raw);
 			LOG.info("Sent batch");
-			dbExecutor.execute(new GenerateBatch());
+			generateBatch();
 		}
 	}
 
@@ -271,6 +297,8 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
+			if (!generateOfferQueued.getAndSet(false))
+				throw new AssertionError();
 			try {
 				Offer o;
 				Transaction txn = db.startTransaction(false);
@@ -305,7 +333,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			recordWriter.writeOffer(offer);
 			LOG.info("Sent offer");
-			dbExecutor.execute(new GenerateOffer());
+			generateOffer();
 		}
 	}
 
@@ -315,6 +343,8 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
+			if (!generateRequestQueued.getAndSet(false))
+				throw new AssertionError();
 			try {
 				Request r;
 				Transaction txn = db.startTransaction(false);
@@ -348,7 +378,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			recordWriter.writeRequest(request);
 			LOG.info("Sent request");
-			dbExecutor.execute(new GenerateRequest());
+			generateRequest();
 		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/sync/RecordReaderImpl.java

@@ -116,7 +116,7 @@ class RecordReaderImpl implements RecordReader {
 	private List<MessageId> readMessageIds() throws IOException {
 		if (payloadLength == 0) throw new FormatException();
 		if (payloadLength % UniqueId.LENGTH != 0) throw new FormatException();
-		List<MessageId> ids = new ArrayList<MessageId>();
+		List<MessageId> ids = new ArrayList<>();
 		for (int off = 0; off < payloadLength; off += UniqueId.LENGTH) {
 			byte[] id = new byte[UniqueId.LENGTH];
 			System.arraycopy(payload, off, id, 0, UniqueId.LENGTH);

bramble-core/src/main/java/org/briarproject/bramble/sync/SimplexOutgoingSession.java

@@ -43,12 +43,7 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(SimplexOutgoingSession.class.getName());
 
-	private static final ThrowingRunnable<IOException> CLOSE =
+	private static final ThrowingRunnable<IOException> CLOSE = () -> {};
-			new ThrowingRunnable<IOException>() {
-				@Override
-				public void run() {
-				}
-			};
 
 	private final DatabaseComponent db;
 	private final Executor dbExecutor;
@@ -71,7 +66,7 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		this.maxLatency = maxLatency;
 		this.recordWriter = recordWriter;
 		outstandingQueries = new AtomicInteger(2); // One per type of record
-		writerTasks = new LinkedBlockingQueue<ThrowingRunnable<IOException>>();
+		writerTasks = new LinkedBlockingQueue<>();
 	}
 
 	@IoExecutor

bramble-core/src/main/java/org/briarproject/bramble/sync/ValidationManagerImpl.java

@@ -64,8 +64,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		this.dbExecutor = dbExecutor;
 		this.validationExecutor = validationExecutor;
 		this.messageFactory = messageFactory;
-		validators = new ConcurrentHashMap<ClientId, MessageValidator>();
+		validators = new ConcurrentHashMap<>();
-		hooks = new ConcurrentHashMap<ClientId, IncomingMessageHook>();
+		hooks = new ConcurrentHashMap<>();
 	}
 
 	@Override
@@ -93,19 +93,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		hooks.put(c, hook);
 	}
 
-	private void validateOutstandingMessagesAsync(final ClientId c) {
+	private void validateOutstandingMessagesAsync(ClientId c) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> validateOutstandingMessages(c));
-			@Override
-			public void run() {
-				validateOutstandingMessages(c);
-			}
-		});
 	}
 
 	@DatabaseExecutor
 	private void validateOutstandingMessages(ClientId c) {
 		try {
-			Queue<MessageId> unvalidated = new LinkedList<MessageId>();
+			Queue<MessageId> unvalidated = new LinkedList<>();
 			Transaction txn = db.startTransaction(true);
 			try {
 				unvalidated.addAll(db.getMessagesToValidate(txn, c));
@@ -119,14 +114,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void validateNextMessageAsync(final Queue<MessageId> unvalidated) {
+	private void validateNextMessageAsync(Queue<MessageId> unvalidated) {
 		if (unvalidated.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> validateNextMessage(unvalidated));
-			@Override
-			public void run() {
-				validateNextMessage(unvalidated);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -158,19 +148,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void deliverOutstandingMessagesAsync(final ClientId c) {
+	private void deliverOutstandingMessagesAsync(ClientId c) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> deliverOutstandingMessages(c));
-			@Override
-			public void run() {
-				deliverOutstandingMessages(c);
-			}
-		});
 	}
 
 	@DatabaseExecutor
 	private void deliverOutstandingMessages(ClientId c) {
 		try {
-			Queue<MessageId> pending = new LinkedList<MessageId>();
+			Queue<MessageId> pending = new LinkedList<>();
 			Transaction txn = db.startTransaction(true);
 			try {
 				pending.addAll(db.getPendingMessages(txn, c));
@@ -184,15 +169,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void deliverNextPendingMessageAsync(
+	private void deliverNextPendingMessageAsync(Queue<MessageId> pending) {
-			final Queue<MessageId> pending) {
 		if (pending.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> deliverNextPendingMessage(pending));
-			@Override
-			public void run() {
-				deliverNextPendingMessage(pending);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -229,8 +208,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 							pending.addAll(getPendingDependents(txn, id));
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare = new LinkedList<MessageId>(
+								toShare = new LinkedList<>(states.keySet());
-										states.keySet());
 							}
 						} else {
 							invalidate = getDependentsToInvalidate(txn, id);
@@ -255,13 +233,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void validateMessageAsync(final Message m, final Group g) {
+	private void validateMessageAsync(Message m, Group g) {
-		validationExecutor.execute(new Runnable() {
+		validationExecutor.execute(() -> validateMessage(m, g));
-			@Override
-			public void run() {
-				validateMessage(m, g);
-			}
-		});
 	}
 
 	@ValidationExecutor
@@ -277,21 +250,16 @@ class ValidationManagerImpl implements ValidationManager, Service,
 			} catch (InvalidMessageException e) {
 				if (LOG.isLoggable(INFO))
 					LOG.log(INFO, e.toString(), e);
-				Queue<MessageId> invalidate = new LinkedList<MessageId>();
+				Queue<MessageId> invalidate = new LinkedList<>();
 				invalidate.add(m.getId());
 				invalidateNextMessageAsync(invalidate);
 			}
 		}
 	}
 
-	private void storeMessageContextAsync(final Message m, final ClientId c,
+	private void storeMessageContextAsync(Message m, ClientId c,
-			final MessageContext result) {
+			MessageContext result) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> storeMessageContext(m, c, result));
-			@Override
-			public void run() {
-				storeMessageContext(m, c, result);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -331,8 +299,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 							pending = getPendingDependents(txn, id);
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare =
+								toShare = new LinkedList<>(dependencies);
-										new LinkedList<MessageId>(dependencies);
 							}
 						} else {
 							invalidate = getDependentsToInvalidate(txn, id);
@@ -378,7 +345,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private Queue<MessageId> getPendingDependents(Transaction txn, MessageId m)
 			throws DbException {
-		Queue<MessageId> pending = new LinkedList<MessageId>();
+		Queue<MessageId> pending = new LinkedList<>();
 		Map<MessageId, State> states = db.getMessageDependents(txn, m);
 		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() == PENDING) pending.add(e.getKey());
@@ -386,19 +353,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		return pending;
 	}
 
-	private void shareOutstandingMessagesAsync(final ClientId c) {
+	private void shareOutstandingMessagesAsync(ClientId c) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> shareOutstandingMessages(c));
-			@Override
-			public void run() {
-				shareOutstandingMessages(c);
-			}
-		});
 	}
 
 	@DatabaseExecutor
 	private void shareOutstandingMessages(ClientId c) {
 		try {
-			Queue<MessageId> toShare = new LinkedList<MessageId>();
+			Queue<MessageId> toShare = new LinkedList<>();
 			Transaction txn = db.startTransaction(true);
 			try {
 				toShare.addAll(db.getMessagesToShare(txn, c));
@@ -418,14 +380,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	 * This method should only be called for messages that have all their
 	 * dependencies delivered and have been delivered themselves.
 	 */
-	private void shareNextMessageAsync(final Queue<MessageId> toShare) {
+	private void shareNextMessageAsync(Queue<MessageId> toShare) {
 		if (toShare.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> shareNextMessage(toShare));
-			@Override
-			public void run() {
-				shareNextMessage(toShare);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -452,14 +409,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void invalidateNextMessageAsync(final Queue<MessageId> invalidate) {
+	private void invalidateNextMessageAsync(Queue<MessageId> invalidate) {
 		if (invalidate.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> invalidateNextMessage(invalidate));
-			@Override
-			public void run() {
-				invalidateNextMessage(invalidate);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -496,7 +448,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private Queue<MessageId> getDependentsToInvalidate(Transaction txn,
 			MessageId m) throws DbException {
-		Queue<MessageId> invalidate = new LinkedList<MessageId>();
+		Queue<MessageId> invalidate = new LinkedList<>();
 		Map<MessageId, State> states = db.getMessageDependents(txn, m);
 		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() != INVALID) invalidate.add(e.getKey());
@@ -514,17 +466,12 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void loadGroupAndValidateAsync(final Message m) {
+	private void loadGroupAndValidateAsync(Message m) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> loadGroupAndValidate(m));
-			@Override
-			public void run() {
-				loadGroupAndValidate(m);
-			}
-		});
 	}
 
 	@DatabaseExecutor
-	private void loadGroupAndValidate(final Message m) {
+	private void loadGroupAndValidate(Message m) {
 		try {
 			Group g;
 			Transaction txn = db.startTransaction(true);

bramble-core/src/main/java/org/briarproject/bramble/transport/KeyManagerImpl.java

@@ -58,15 +58,14 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		this.pluginConfig = pluginConfig;
 		this.transportKeyManagerFactory = transportKeyManagerFactory;
 		// Use a ConcurrentHashMap as a thread-safe set
-		activeContacts = new ConcurrentHashMap<ContactId, Boolean>();
+		activeContacts = new ConcurrentHashMap<>();
-		managers = new ConcurrentHashMap<TransportId, TransportKeyManager>();
+		managers = new ConcurrentHashMap<>();
 	}
 
 	@Override
 	public void startService() throws ServiceException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		Map<TransportId, Integer> transports =
+		Map<TransportId, Integer> transports = new HashMap<>();
-				new HashMap<TransportId, Integer>();
 		for (SimplexPluginFactory f : pluginConfig.getSimplexFactories())
 			transports.put(f.getId(), f.getMaxLatency());
 		for (DuplexPluginFactory f : pluginConfig.getDuplexFactories())
@@ -156,14 +155,10 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		}
 	}
 
-	private void removeContact(final ContactId c) {
+	private void removeContact(ContactId c) {
 		activeContacts.remove(c);
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> {
-			@Override
+			for (TransportKeyManager m : managers.values()) m.removeContact(c);
-			public void run() {
-				for (TransportKeyManager m : managers.values())
-					m.removeContact(c);
-			}
 		});
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/transport/ReorderingWindow.java

@@ -45,7 +45,7 @@ class ReorderingWindow {
 	}
 
 	List<Long> getUnseen() {
-		List<Long> unseen = new ArrayList<Long>(seen.length);
+		List<Long> unseen = new ArrayList<>(seen.length);
 		for (int i = 0; i < seen.length; i++)
 			if (!seen[i]) unseen.add(base + i);
 		return unseen;
@@ -69,8 +69,8 @@ class ReorderingWindow {
 			return new Change(added, removed);
 		}
 		// Record the elements that will be added and removed
-		List<Long> added = new ArrayList<Long>(slide);
+		List<Long> added = new ArrayList<>(slide);
-		List<Long> removed = new ArrayList<Long>(slide);
+		List<Long> removed = new ArrayList<>(slide);
 		for (int i = 0; i < slide; i++) {
 			if (!seen[i]) removed.add(base + i);
 			added.add(base + seen.length + i);

bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerImpl.java

@@ -65,9 +65,9 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		this.transportId = transportId;
 		rotationPeriodLength = maxLatency + MAX_CLOCK_DIFFERENCE;
 		lock = new ReentrantLock();
-		inContexts = new HashMap<Bytes, TagContext>();
+		inContexts = new HashMap<>();
-		outContexts = new HashMap<ContactId, MutableOutgoingKeys>();
+		outContexts = new HashMap<>();
-		keys = new HashMap<ContactId, MutableTransportKeys>();
+		keys = new HashMap<>();
 	}
 
 	@Override
@@ -134,32 +134,22 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	private void scheduleKeyRotation(long now) {
-		Runnable task = new Runnable() {
-			@Override
-			public void run() {
-				rotateKeys();
-			}
-		};
 		long delay = rotationPeriodLength - now % rotationPeriodLength;
-		scheduler.schedule(task, delay, MILLISECONDS);
+		scheduler.schedule((Runnable) this::rotateKeys, delay, MILLISECONDS);
 	}
 
 	private void rotateKeys() {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> {
-			@Override
+			try {
-			public void run() {
+				Transaction txn = db.startTransaction(false);
 				try {
-					Transaction txn = db.startTransaction(false);
+					rotateKeys(txn);
-					try {
+					db.commitTransaction(txn);
-						rotateKeys(txn);
+				} finally {
-						db.commitTransaction(txn);
+					db.endTransaction(txn);
-					} finally {
-						db.endTransaction(txn);
-					}
-				} catch (DbException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
 				}
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
 		});
 	}
@@ -272,8 +262,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		lock.lock();
 		try {
 			// Rotate the keys to the current rotation period
-			Map<ContactId, TransportKeys> snapshot =
+			Map<ContactId, TransportKeys> snapshot = new HashMap<>();
-					new HashMap<ContactId, TransportKeys>();
 			for (Entry<ContactId, MutableTransportKeys> e : keys.entrySet())
 				snapshot.put(e.getKey(), e.getValue().snapshot());
 			RotationResult rotationResult = rotateKeys(snapshot, now);
@@ -311,8 +300,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		private final Map<ContactId, TransportKeys> current, rotated;
 
 		private RotationResult() {
-			current = new HashMap<ContactId, TransportKeys>();
+			current = new HashMap<>();
-			rotated = new HashMap<ContactId, TransportKeys>();
+			rotated = new HashMap<>();
 		}
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/PoliteExecutorTest.java

@@ -24,16 +24,13 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newSingleThreadExecutor();
 		// Allow all the tasks to be delegated straight away
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, TASKS * 2);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch latch = new CountDownLatch(TASKS);
+		CountDownLatch latch = new CountDownLatch(TASKS);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				list.add(result);
-				public void run() {
+				latch.countDown();
-					list.add(result);
-					latch.countDown();
-				}
 			});
 		}
 		// Wait for all the tasks to finish
@@ -49,16 +46,13 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newSingleThreadExecutor();
 		// Allow two tasks to be delegated at a time
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, 2);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch latch = new CountDownLatch(TASKS);
+		CountDownLatch latch = new CountDownLatch(TASKS);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				list.add(result);
-				public void run() {
+				latch.countDown();
-					list.add(result);
-					latch.countDown();
-				}
 			});
 		}
 		// Wait for all the tasks to finish
@@ -73,23 +67,20 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newCachedThreadPool();
 		// Allow all the tasks to be delegated straight away
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, TASKS * 2);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch[] latches = new CountDownLatch[TASKS];
+		CountDownLatch[] latches = new CountDownLatch[TASKS];
 		for (int i = 0; i < TASKS; i++) latches[i] = new CountDownLatch(1);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				try {
-				public void run() {
+					// Each task waits for the next task, if any, to finish
-					try {
+					if (result < TASKS - 1) latches[result + 1].await();
-						// Each task waits for the next task, if any, to finish
+					list.add(result);
-						if (result < TASKS - 1) latches[result + 1].await();
+				} catch (InterruptedException e) {
-						list.add(result);
+					fail();
-					} catch (InterruptedException e) {
-						fail();
-					}
-					latches[result].countDown();
 				}
+				latches[result].countDown();
 			});
 		}
 		// Wait for all the tasks to finish
@@ -104,22 +95,19 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newCachedThreadPool();
 		// Allow one task to be delegated at a time
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, 1);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch latch = new CountDownLatch(TASKS);
+		CountDownLatch latch = new CountDownLatch(TASKS);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				try {
-				public void run() {
+					// Each task runs faster than the previous task
-					try {
+					Thread.sleep(TASKS - result);
-						// Each task runs faster than the previous task
+					list.add(result);
-						Thread.sleep(TASKS - result);
+				} catch (InterruptedException e) {
-						list.add(result);
+					fail();
-					} catch (InterruptedException e) {
-						fail();
-					}
-					latch.countDown();
 				}
+				latch.countDown();
 			});
 		}
 		// Wait for all the tasks to finish

bramble-core/src/test/java/org/briarproject/bramble/client/BdfMessageValidatorTest.java

@@ -83,9 +83,9 @@ public class BdfMessageValidatorTest extends ValidatorTestCase {
 
 	@Test(expected = InvalidMessageException.class)
 	public void testRejectsTooShortMessage() throws Exception {
-		final byte[] invalidRaw = new byte[MESSAGE_HEADER_LENGTH];
+		byte[] invalidRaw = new byte[MESSAGE_HEADER_LENGTH];
 		// Use a mock message so the length of the raw message can be invalid
-		final Message invalidMessage = context.mock(Message.class);
+		Message invalidMessage = context.mock(Message.class);
 
 		context.checking(new Expectations() {{
 			oneOf(invalidMessage).getTimestamp();
@@ -101,8 +101,8 @@ public class BdfMessageValidatorTest extends ValidatorTestCase {
 
 	@Test
 	public void testAcceptsMinLengthMessage() throws Exception {
-		final byte[] shortRaw = new byte[MESSAGE_HEADER_LENGTH + 1];
+		byte[] shortRaw = new byte[MESSAGE_HEADER_LENGTH + 1];
-		final Message shortMessage =
+		Message shortMessage =
 				new Message(messageId, groupId, timestamp, shortRaw);
 
 		context.checking(new Expectations() {{

bramble-core/src/test/java/org/briarproject/bramble/client/ClientHelperImplTest.java

@@ -20,7 +20,7 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.test.BrambleTestCase;
-import org.briarproject.bramble.test.TestUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.jmock.Expectations;
 import org.jmock.Mockery;
 import org.junit.Test;
@@ -65,7 +65,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 			new Message(messageId, groupId, timestamp, rawMessage);
 	private final Metadata metadata = new Metadata();
 	private final BdfList list = BdfList.of("Sign this!", getRandomBytes(42));
-	private final String label = TestUtils.getRandomString(5);
+	private final String label = StringUtils.getRandomString(5);
 
 	public ClientHelperImplTest() {
 		clientHelper =
@@ -76,8 +76,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testAddLocalMessage() throws Exception {
-		final boolean shared = true;
+		boolean shared = true;
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -95,7 +95,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testCreateMessage() throws Exception {
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 
 		context.checking(new Expectations() {{
 			oneOf(messageFactory).createMessage(groupId, timestamp, bytes);
@@ -107,7 +107,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageAsList() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		expectToList(true);
 		context.checking(new Expectations() {{
@@ -125,7 +125,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetGroupMetadataAsDictionary() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -145,7 +145,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageMetadataAsDictionary() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -165,10 +165,9 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageMetadataAsDictionaryMap() throws Exception {
-		final Map<MessageId, BdfDictionary> map =
+		Map<MessageId, BdfDictionary> map = new HashMap<>();
-				new HashMap<MessageId, BdfDictionary>();
 		map.put(messageId, dictionary);
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -188,14 +187,13 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageMetadataAsDictionaryQuery() throws Exception {
-		final Map<MessageId, BdfDictionary> map =
+		Map<MessageId, BdfDictionary> map = new HashMap<>();
-				new HashMap<MessageId, BdfDictionary>();
 		map.put(messageId, dictionary);
-		final BdfDictionary query =
+		BdfDictionary query =
 				BdfDictionary.of(new BdfEntry("query", "me"));
-		final Metadata queryMetadata = new Metadata();
+		Metadata queryMetadata = new Metadata();
 		queryMetadata.put("query", getRandomBytes(42));
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -217,7 +215,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testMergeGroupMetadata() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -235,7 +233,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testMergeMessageMetadata() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -282,10 +280,10 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testSign() throws Exception {
-		final byte[] privateKey = getRandomBytes(42);
+		byte[] privateKey = getRandomBytes(42);
-		final byte[] signed = getRandomBytes(42);
+		byte[] signed = getRandomBytes(42);
 
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 		context.checking(new Expectations() {{
 			oneOf(cryptoComponent).sign(label, bytes, privateKey);
 			will(returnValue(signed));
@@ -297,8 +295,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testVerifySignature() throws Exception {
-		final byte[] publicKey = getRandomBytes(42);
+		byte[] publicKey = getRandomBytes(42);
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 
 		context.checking(new Expectations() {{
 			oneOf(cryptoComponent).verify(label, bytes, publicKey, rawMessage);
@@ -311,8 +309,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testVerifyWrongSignature() throws Exception {
-		final byte[] publicKey = getRandomBytes(42);
+		byte[] publicKey = getRandomBytes(42);
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 
 		context.checking(new Expectations() {{
 			oneOf(cryptoComponent).verify(label, bytes, publicKey, rawMessage);
@@ -329,8 +327,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		}
 	}
 
-	private byte[] expectToByteArray(final BdfList list) throws Exception {
+	private byte[] expectToByteArray(BdfList list) throws Exception {
-		final BdfWriter bdfWriter = context.mock(BdfWriter.class);
+		BdfWriter bdfWriter = context.mock(BdfWriter.class);
 
 		context.checking(new Expectations() {{
 			oneOf(bdfWriterFactory)
@@ -341,8 +339,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		return new byte[0];
 	}
 
-	private void expectToList(final boolean eof) throws Exception {
+	private void expectToList(boolean eof) throws Exception {
-		final BdfReader bdfReader = context.mock(BdfReader.class);
+		BdfReader bdfReader = context.mock(BdfReader.class);
 
 		context.checking(new Expectations() {{
 			oneOf(bdfReaderFactory)

bramble-core/src/test/java/org/briarproject/bramble/contact/ContactManagerImplTest.java

@@ -46,10 +46,10 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testAddContact() throws Exception {
-		final SecretKey master = getSecretKey();
+		SecretKey master = getSecretKey();
-		final long timestamp = 42;
+		long timestamp = 42;
-		final boolean alice = true;
+		boolean alice = true;
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -64,14 +64,13 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 			oneOf(db).endTransaction(txn);
 		}});
 
-		assertEquals(contactId, contactManager
+		assertEquals(contactId, contactManager.addContact(remote, local,
-				.addContact(remote, local, master, timestamp, alice, verified,
+				master, timestamp, alice, verified, active));
-						active));
 	}
 
 	@Test
 	public void testGetContact() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -86,8 +85,8 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testGetContactByAuthor() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
-		final Collection<Contact> contacts = Collections.singleton(contact);
+		Collection<Contact> contacts = Collections.singleton(contact);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -102,7 +101,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test(expected = NoSuchContactException.class)
 	public void testGetContactByUnknownAuthor() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -116,8 +115,8 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test(expected = NoSuchContactException.class)
 	public void testGetContactByUnknownLocalAuthor() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
-		final Collection<Contact> contacts = Collections.singleton(contact);
+		Collection<Contact> contacts = Collections.singleton(contact);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -132,10 +131,9 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testActiveContacts() throws Exception {
 		Collection<Contact> activeContacts = Collections.singletonList(contact);
-		final Collection<Contact> contacts =
+		Collection<Contact> contacts = new ArrayList<>(activeContacts);
-				new ArrayList<Contact>(activeContacts);
 		contacts.add(new Contact(new ContactId(3), remote, local, true, false));
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -150,7 +148,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testRemoveContact() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
 			will(returnValue(txn));
@@ -166,7 +164,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testSetContactActive() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 		context.checking(new Expectations() {{
 			oneOf(db).setContactActive(txn, contactId, active);
 		}});
@@ -176,7 +174,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testContactExists() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));

bramble-core/src/test/java/org/briarproject/bramble/crypto/EllipticCurvePerformanceTest.java

@@ -69,7 +69,7 @@ public class EllipticCurvePerformanceTest {
 		ECPublicKeyParameters public2 =
 				(ECPublicKeyParameters) keyPair2.getPublic();
 		// Time some ECDH key agreements
-		List<Long> samples = new ArrayList<Long>();
+		List<Long> samples = new ArrayList<>();
 		for (int i = 0; i < SAMPLES; i++) {
 			ECDHCBasicAgreement agreement = new ECDHCBasicAgreement();
 			long start = System.nanoTime();
@@ -79,7 +79,7 @@ public class EllipticCurvePerformanceTest {
 		}
 		long agreementMedian = median(samples);
 		// Time some signatures
-		List<byte[]> signatures = new ArrayList<byte[]>();
+		List<byte[]> signatures = new ArrayList<>();
 		samples.clear();
 		for (int i = 0; i < SAMPLES; i++) {
 			Digest digest = new Blake2sDigest();

bramble-core/src/test/java/org/briarproject/bramble/crypto/HashTest.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestSecureRandomProvider;
 import org.briarproject.bramble.test.TestUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.junit.Test;
 
 import java.util.Arrays;
@@ -15,7 +16,7 @@ public class HashTest extends BrambleTestCase {
 
 	private final CryptoComponent crypto;
 
-	private final String label = TestUtils.getRandomString(42);
+	private final String label = StringUtils.getRandomString(42);
 	private final byte[] inputBytes = TestUtils.getRandomBytes(123);
 	private final byte[] inputBytes1 = TestUtils.getRandomBytes(234);
 	private final byte[] inputBytes2 = new byte[0];
@@ -40,7 +41,7 @@ public class HashTest extends BrambleTestCase {
 
 	@Test
 	public void testDifferentLabelsProduceDifferentHashes() {
-		String label2 = TestUtils.getRandomString(42);
+		String label2 = StringUtils.getRandomString(42);
 		byte[] hash1 = crypto.hash(label, inputBytes, inputBytes1, inputBytes2);
 		byte[] hash2 =
 				crypto.hash(label2, inputBytes, inputBytes1, inputBytes2);

bramble-core/src/test/java/org/briarproject/bramble/crypto/KeyDerivationTest.java

@@ -145,7 +145,7 @@ public class KeyDerivationTest extends BrambleTestCase {
 	}
 
 	private void assertAllDifferent(TransportKeys... transportKeys) {
-		List<SecretKey> secretKeys = new ArrayList<SecretKey>();
+		List<SecretKey> secretKeys = new ArrayList<>();
 		for (TransportKeys k : transportKeys) {
 			secretKeys.add(k.getPreviousIncomingKeys().getTagKey());
 			secretKeys.add(k.getPreviousIncomingKeys().getHeaderKey());
@@ -160,7 +160,7 @@ public class KeyDerivationTest extends BrambleTestCase {
 	}
 
 	private void assertAllDifferent(List<SecretKey> keys) {
-		Set<Bytes> set = new HashSet<Bytes>();
+		Set<Bytes> set = new HashSet<>();
 		for (SecretKey k : keys) assertTrue(set.add(new Bytes(k.getBytes())));
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/crypto/SignatureTest.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestSecureRandomProvider;
 import org.briarproject.bramble.test.TestUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.junit.Test;
 
 import java.util.Arrays;
@@ -18,7 +19,7 @@ public class SignatureTest extends BrambleTestCase {
 	private final CryptoComponent crypto;
 
 	private final byte[] publicKey, privateKey;
-	private final String label = TestUtils.getRandomString(42);
+	private final String label = StringUtils.getRandomString(42);
 	private final byte[] inputBytes = TestUtils.getRandomBytes(123);
 
 	public SignatureTest() {
@@ -64,7 +65,7 @@ public class SignatureTest extends BrambleTestCase {
 	public void testDifferentLabelsProduceDifferentSignatures()
 			throws Exception {
 		// Generate a second label
-		String label2 = TestUtils.getRandomString(42);
+		String label2 = StringUtils.getRandomString(42);
 		// Calculate the signature with different inputs
 		// the results should be different
 		byte[] sig1 = crypto.sign(label, inputBytes, privateKey);
@@ -100,7 +101,7 @@ public class SignatureTest extends BrambleTestCase {
 	@Test
 	public void testDifferentLabelFailsVerification() throws Exception {
 		// Generate a second label
-		String label2 = TestUtils.getRandomString(42);
+		String label2 = StringUtils.getRandomString(42);
 		// calculate the signature with different label, should fail to verify
 		byte[] sig = crypto.sign(label, inputBytes, privateKey);
 		assertFalse(crypto.verify(label2, inputBytes, publicKey, sig));

bramble-core/src/test/java/org/briarproject/bramble/crypto/TagEncodingTest.java

@@ -28,7 +28,7 @@ public class TagEncodingTest extends BrambleTestCase {
 
 	@Test
 	public void testKeyAffectsTag() throws Exception {
-		Set<Bytes> set = new HashSet<Bytes>();
+		Set<Bytes> set = new HashSet<>();
 		for (int i = 0; i < 100; i++) {
 			byte[] tag = new byte[TAG_LENGTH];
 			SecretKey tagKey = TestUtils.getSecretKey();
@@ -39,7 +39,7 @@ public class TagEncodingTest extends BrambleTestCase {
 
 	@Test
 	public void testProtocolVersionAffectsTag() throws Exception {
-		Set<Bytes> set = new HashSet<Bytes>();
+		Set<Bytes> set = new HashSet<>();
 		for (int i = 0; i < 100; i++) {
 			byte[] tag = new byte[TAG_LENGTH];
 			crypto.encodeTag(tag, tagKey, PROTOCOL_VERSION + i, streamNumber);
@@ -49,7 +49,7 @@ public class TagEncodingTest extends BrambleTestCase {
 
 	@Test
 	public void testStreamNumberAffectsTag() throws Exception {
-		Set<Bytes> set = new HashSet<Bytes>();
+		Set<Bytes> set = new HashSet<>();
 		for (int i = 0; i < 100; i++) {
 			byte[] tag = new byte[TAG_LENGTH];
 			crypto.encodeTag(tag, tagKey, PROTOCOL_VERSION, streamNumber + i);

bramble-core/src/test/java/org/briarproject/bramble/data/BdfReaderImplTest.java

@@ -4,7 +4,6 @@ import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.test.BrambleTestCase;
-import org.briarproject.bramble.test.TestUtils;
 import org.briarproject.bramble.util.StringUtils;
 import org.junit.Test;
 
@@ -159,7 +158,7 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test
 	public void testReadString8() throws Exception {
-		String longest = TestUtils.getRandomString(Byte.MAX_VALUE);
+		String longest = StringUtils.getRandomString(Byte.MAX_VALUE);
 		String longHex = StringUtils.toHexString(longest.getBytes("UTF-8"));
 		// "foo", the empty string, and 127 random letters
 		setContents("41" + "03" + "666F6F" + "41" + "00" +
@@ -181,7 +180,7 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test
 	public void testSkipString8() throws Exception {
-		String longest = TestUtils.getRandomString(Byte.MAX_VALUE);
+		String longest = StringUtils.getRandomString(Byte.MAX_VALUE);
 		String longHex = StringUtils.toHexString(longest.getBytes("UTF-8"));
 		// "foo", the empty string, and 127 random letters
 		setContents("41" + "03" + "666F6F" + "41" + "00" +
@@ -194,9 +193,9 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test
 	public void testReadString16() throws Exception {
-		String shortest = TestUtils.getRandomString(Byte.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Byte.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
-		String longest = TestUtils.getRandomString(Short.MAX_VALUE);
+		String longest = StringUtils.getRandomString(Short.MAX_VALUE);
 		String longHex = StringUtils.toHexString(longest.getBytes("UTF-8"));
 		// 128 random letters and 2^15 -1 random letters
 		setContents("42" + "0080" + shortHex + "42" + "7FFF" + longHex);
@@ -207,7 +206,7 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test(expected = FormatException.class)
 	public void testReadString16ChecksMaxLength() throws Exception {
-		String shortest = TestUtils.getRandomString(Byte.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Byte.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
 		// 128 random letters, twice
 		setContents("42" + "0080" + shortHex + "42" + "0080" + shortHex);
@@ -218,9 +217,9 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test
 	public void testSkipString16() throws Exception {
-		String shortest = TestUtils.getRandomString(Byte.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Byte.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
-		String longest = TestUtils.getRandomString(Short.MAX_VALUE);
+		String longest = StringUtils.getRandomString(Short.MAX_VALUE);
 		String longHex = StringUtils.toHexString(longest.getBytes("UTF-8"));
 		// 128 random letters and 2^15 - 1 random letters
 		setContents("42" + "0080" + shortHex + "42" + "7FFF" + longHex);
@@ -231,7 +230,7 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test
 	public void testReadString32() throws Exception {
-		String shortest = TestUtils.getRandomString(Short.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Short.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
 		// 2^15 random letters
 		setContents("44" + "00008000" + shortHex);
@@ -241,7 +240,7 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test(expected = FormatException.class)
 	public void testReadString32ChecksMaxLength() throws Exception {
-		String shortest = TestUtils.getRandomString(Short.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Short.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
 		// 2^15 random letters, twice
 		setContents("44" + "00008000" + shortHex +
@@ -253,7 +252,7 @@ public class BdfReaderImplTest extends BrambleTestCase {
 
 	@Test
 	public void testSkipString32() throws Exception {
-		String shortest = TestUtils.getRandomString(Short.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Short.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
 		// 2^15 random letters, twice
 		setContents("44" + "00008000" + shortHex +

bramble-core/src/test/java/org/briarproject/bramble/data/BdfWriterImplTest.java

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.data;
 
 import org.briarproject.bramble.test.BrambleTestCase;
-import org.briarproject.bramble.test.TestUtils;
 import org.briarproject.bramble.util.StringUtils;
 import org.junit.Before;
 import org.junit.Test;
@@ -81,7 +80,7 @@ public class BdfWriterImplTest extends BrambleTestCase {
 
 	@Test
 	public void testWriteString8() throws IOException {
-		String longest = TestUtils.getRandomString(Byte.MAX_VALUE);
+		String longest = StringUtils.getRandomString(Byte.MAX_VALUE);
 		String longHex = StringUtils.toHexString(longest.getBytes("UTF-8"));
 		w.writeString("foo bar baz bam ");
 		w.writeString(longest);
@@ -93,9 +92,9 @@ public class BdfWriterImplTest extends BrambleTestCase {
 
 	@Test
 	public void testWriteString16() throws IOException {
-		String shortest = TestUtils.getRandomString(Byte.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Byte.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
-		String longest = TestUtils.getRandomString(Short.MAX_VALUE);
+		String longest = StringUtils.getRandomString(Short.MAX_VALUE);
 		String longHex = StringUtils.toHexString(longest.getBytes("UTF-8"));
 		w.writeString(shortest);
 		w.writeString(longest);
@@ -106,7 +105,7 @@ public class BdfWriterImplTest extends BrambleTestCase {
 
 	@Test
 	public void testWriteString32() throws IOException {
-		String shortest = TestUtils.getRandomString(Short.MAX_VALUE + 1);
+		String shortest = StringUtils.getRandomString(Short.MAX_VALUE + 1);
 		String shortHex = StringUtils.toHexString(shortest.getBytes("UTF-8"));
 		w.writeString(shortest);
 		// STRING_32 tag, length 2^15, UTF-8 bytes
@@ -155,7 +154,7 @@ public class BdfWriterImplTest extends BrambleTestCase {
 
 	@Test
 	public void testWriteList() throws IOException {
-		List<Object> l = new ArrayList<Object>();
+		List<Object> l = new ArrayList<>();
 		for (int i = 0; i < 3; i++) l.add(i);
 		w.writeList(l);
 		// LIST tag, elements as integers, END tag
@@ -164,7 +163,7 @@ public class BdfWriterImplTest extends BrambleTestCase {
 
 	@Test
 	public void testListCanContainNull() throws IOException {
-		List<Object> l = new ArrayList<Object>();
+		List<Object> l = new ArrayList<>();
 		l.add(1);
 		l.add(null);
 		l.add(NULL_VALUE);
@@ -177,7 +176,7 @@ public class BdfWriterImplTest extends BrambleTestCase {
 	@Test
 	public void testWriteDictionary() throws IOException {
 		// Use LinkedHashMap to get predictable iteration order
-		Map<String, Object> m = new LinkedHashMap<String, Object>();
+		Map<String, Object> m = new LinkedHashMap<>();
 		for (int i = 0; i < 4; i++) m.put(String.valueOf(i), i);
 		w.writeDictionary(m);
 		// DICTIONARY tag, keys as strings and values as integers, END tag
@@ -216,12 +215,12 @@ public class BdfWriterImplTest extends BrambleTestCase {
 
 	@Test
 	public void testWriteNestedDictionariesAndLists() throws IOException {
-		Map<String, Object> inner = new LinkedHashMap<String, Object>();
+		Map<String, Object> inner = new LinkedHashMap<>();
 		inner.put("bar", new byte[0]);
-		List<Object> list = new ArrayList<Object>();
+		List<Object> list = new ArrayList<>();
 		list.add(1);
 		list.add(inner);
-		Map<String, Object> outer = new LinkedHashMap<String, Object>();
+		Map<String, Object> outer = new LinkedHashMap<>();
 		outer.put("foo", list);
 		w.writeDictionary(outer);
 		// DICTIONARY tag, "foo" as string, LIST tag, 1 as integer,

bramble-core/src/test/java/org/briarproject/bramble/data/MetadataEncoderParserIntegrationTest.java

@@ -99,7 +99,7 @@ public class MetadataEncoderParserIntegrationTest extends BrambleTestCase {
 
 	@Test
 	public void testList() throws FormatException {
-		List<Long> l = new ArrayList<Long>(4);
+		List<Long> l = new ArrayList<>(4);
 		l.add(42L);
 		l.add(1337L);
 		l.add(Long.MIN_VALUE);
@@ -114,7 +114,7 @@ public class MetadataEncoderParserIntegrationTest extends BrambleTestCase {
 
 	@Test
 	public void testDictionary() throws FormatException {
-		Map<String, Boolean> m = new HashMap<String, Boolean>();
+		Map<String, Boolean> m = new HashMap<>();
 		m.put("1", true);
 		m.put("2", false);
 
@@ -130,19 +130,19 @@ public class MetadataEncoderParserIntegrationTest extends BrambleTestCase {
 
 	@Test
 	public void testComplexDictionary() throws FormatException {
-		Map<String, List> m = new HashMap<String, List>();
+		Map<String, List> m = new HashMap<>();
-		List<String> one = new ArrayList<String>(3);
+		List<String> one = new ArrayList<>(3);
 		one.add("\uFDD0");
 		one.add("\uFDD1");
 		one.add("\uFDD2");
 		m.put("One", one);
-		List<String> two = new ArrayList<String>(2);
+		List<String> two = new ArrayList<>(2);
 		two.add("\u0080");
 		two.add("\uD800\uDC00");
 		m.put("Two", two);
 		d.put("test", m);
 
-		Map<String, Boolean> m2 = new HashMap<String, Boolean>();
+		Map<String, Boolean> m2 = new HashMap<>();
 		m2.put("should be true", true);
 		d.put("another test", m2);
 

bramble-core/src/test/java/org/briarproject/bramble/db/BasicH2Test.java

@@ -2,6 +2,7 @@ package org.briarproject.bramble.db;
 
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -48,8 +49,8 @@ public class BasicH2Test extends BrambleTestCase {
 		createTable(connection);
 		// Generate an ID and two names
 		byte[] id = TestUtils.getRandomId();
-		String oldName = TestUtils.getRandomString(50);
+		String oldName = StringUtils.getRandomString(50);
-		String newName = TestUtils.getRandomString(50);
+		String newName = StringUtils.getRandomString(50);
 		// Insert the ID and old name into the table
 		insertRow(id, oldName);
 		// Check that the old name can be retrieved using the ID
@@ -78,8 +79,8 @@ public class BasicH2Test extends BrambleTestCase {
 		String[] newNames = new String[BATCH_SIZE];
 		for (int i = 0; i < BATCH_SIZE; i++) {
 			ids[i] = TestUtils.getRandomId();
-			oldNames[i] = TestUtils.getRandomString(50);
+			oldNames[i] = StringUtils.getRandomString(50);
-			newNames[i] = TestUtils.getRandomString(50);
+			newNames[i] = StringUtils.getRandomString(50);
 		}
 		// Insert the IDs and old names into the table as a batch
 		insertBatch(ids, oldNames);
@@ -322,7 +323,7 @@ public class BasicH2Test extends BrambleTestCase {
 
 	private List<String> getNames() throws SQLException {
 		String sql = "SELECT name FROM foo ORDER BY uniqueId";
-		List<String> names = new ArrayList<String>();
+		List<String> names = new ArrayList<>();
 		try {
 			PreparedStatement ps = connection.prepareStatement(sql);
 			ResultSet rs = ps.executeQuery();

bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java

@@ -47,10 +47,10 @@ import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
 import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
-import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.TestUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.jmock.Expectations;
-import org.jmock.Mockery;
 import org.junit.Test;
 
 import java.util.ArrayList;
@@ -73,7 +73,13 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.fail;
 
-public class DatabaseComponentImplTest extends BrambleTestCase {
+public class DatabaseComponentImplTest extends BrambleMockTestCase {
+
+	@SuppressWarnings("unchecked")
+	private final Database<Object> database = context.mock(Database.class);
+	private final ShutdownManager shutdown =
+			context.mock(ShutdownManager.class);
+	private final EventBus eventBus = context.mock(EventBus.class);
 
 	private final Object txn = new Object();
 	private final ClientId clientId;
@@ -94,7 +100,7 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 	private final Contact contact;
 
 	public DatabaseComponentImplTest() {
-		clientId = new ClientId(TestUtils.getRandomString(5));
+		clientId = new ClientId(StringUtils.getRandomString(5));
 		groupId = new GroupId(TestUtils.getRandomId());
 		byte[] descriptor = new byte[MAX_GROUP_DESCRIPTOR_LENGTH];
 		group = new Group(groupId, clientId, descriptor);
@@ -119,18 +125,13 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 
 	private DatabaseComponent createDatabaseComponent(Database<Object> database,
 			EventBus eventBus, ShutdownManager shutdown) {
-		return new DatabaseComponentImpl<Object>(database, Object.class,
+		return new DatabaseComponentImpl<>(database, Object.class, eventBus,
-				eventBus, shutdown);
+				shutdown);
 	}
 
 	@Test
-	@SuppressWarnings("unchecked")
 	public void testSimpleCalls() throws Exception {
-		final int shutdownHandle = 12345;
+		int shutdownHandle = 12345;
-		Mockery context = new Mockery();
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// open()
 			oneOf(database).open();
@@ -193,7 +194,6 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 			// endTransaction()
 			oneOf(database).commitTransaction(txn);
 			// close()
-			oneOf(shutdown).removeShutdownHook(shutdownHandle);
 			oneOf(database).close();
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
@@ -220,18 +220,11 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 			db.endTransaction(transaction);
 		}
 		db.close();
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testLocalMessagesAreNotStoredUnlessGroupExists()
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -251,17 +244,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testAddLocalMessage() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -293,18 +279,11 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testVariousMethodsThrowExceptionIfContactIsMissing()
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// Check whether the contact is in the DB (which it's not)
 			exactly(18).of(database).startTransaction();
@@ -499,18 +478,11 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testVariousMethodsThrowExceptionIfLocalAuthorIsMissing()
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// Check whether the pseudonym is in the DB (which it's not)
 			exactly(3).of(database).startTransaction();
@@ -551,18 +523,11 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testVariousMethodsThrowExceptionIfGroupIsMissing()
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// Check whether the group is in the DB (which it's not)
 			exactly(8).of(database).startTransaction();
@@ -656,18 +621,11 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testVariousMethodsThrowExceptionIfMessageIsMissing()
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// Check whether the message is in the DB (which it's not)
 			exactly(11).of(database).startTransaction();
@@ -791,18 +749,11 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testVariousMethodsThrowExceptionIfTransportIsMissing()
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// startTransaction()
 			oneOf(database).startTransaction();
@@ -889,19 +840,12 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testGenerateAck() throws Exception {
-		final Collection<MessageId> messagesToAck = Arrays.asList(messageId,
+		Collection<MessageId> messagesToAck = Arrays.asList(messageId,
 				messageId1);
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -924,20 +868,13 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testGenerateBatch() throws Exception {
-		final byte[] raw1 = new byte[size];
+		byte[] raw1 = new byte[size];
-		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
+		Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
-		final Collection<byte[]> messages = Arrays.asList(raw, raw1);
+		Collection<byte[]> messages = Arrays.asList(raw, raw1);
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -968,19 +905,12 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testGenerateOffer() throws Exception {
-		final MessageId messageId1 = new MessageId(TestUtils.getRandomId());
+		MessageId messageId1 = new MessageId(TestUtils.getRandomId());
-		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
+		Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1006,19 +936,12 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testGenerateRequest() throws Exception {
-		final MessageId messageId1 = new MessageId(TestUtils.getRandomId());
+		MessageId messageId1 = new MessageId(TestUtils.getRandomId());
-		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
+		Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1041,20 +964,13 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testGenerateRequestedBatch() throws Exception {
-		final byte[] raw1 = new byte[size];
+		byte[] raw1 = new byte[size];
-		final Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
+		Collection<MessageId> ids = Arrays.asList(messageId, messageId1);
-		final Collection<byte[]> messages = Arrays.asList(raw, raw1);
+		Collection<byte[]> messages = Arrays.asList(raw, raw1);
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1086,17 +1002,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testReceiveAck() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1119,17 +1028,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testReceiveMessage() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1174,17 +1076,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testReceiveDuplicateMessage() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1211,17 +1106,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testReceiveMessageWithoutVisibleGroup() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1241,20 +1129,13 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testReceiveOffer() throws Exception {
-		final MessageId messageId1 = new MessageId(TestUtils.getRandomId());
+		MessageId messageId1 = new MessageId(TestUtils.getRandomId());
-		final MessageId messageId2 = new MessageId(TestUtils.getRandomId());
+		MessageId messageId2 = new MessageId(TestUtils.getRandomId());
-		final MessageId messageId3 = new MessageId(TestUtils.getRandomId());
+		MessageId messageId3 = new MessageId(TestUtils.getRandomId());
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1295,17 +1176,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testReceiveRequest() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1329,17 +1203,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testChangingVisibilityCallsListeners() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1369,18 +1236,11 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testNotChangingVisibilityDoesNotCallListeners()
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1402,20 +1262,13 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testTransportKeys() throws Exception {
-		final TransportKeys transportKeys = createTransportKeys();
+		TransportKeys transportKeys = createTransportKeys();
-		final Map<ContactId, TransportKeys> keys = Collections.singletonMap(
+		Map<ContactId, TransportKeys> keys = Collections.singletonMap(
 				contactId, transportKeys);
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// startTransaction()
 			oneOf(database).startTransaction();
@@ -1445,8 +1298,6 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	private TransportKeys createTransportKeys() {
@@ -1471,19 +1322,14 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 
 	@Test
 	public void testMergeSettings() throws Exception {
-		final Settings before = new Settings();
+		Settings before = new Settings();
 		before.put("foo", "bar");
 		before.put("baz", "bam");
-		final Settings update = new Settings();
+		Settings update = new Settings();
 		update.put("baz", "qux");
-		final Settings merged = new Settings();
+		Settings merged = new Settings();
 		merged.put("foo", "bar");
 		merged.put("baz", "qux");
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			// startTransaction()
 			oneOf(database).startTransaction();
@@ -1513,8 +1359,6 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test(expected = IllegalStateException.class)
@@ -1544,12 +1388,6 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 	private void testCannotStartTransactionDuringTransaction(
 			boolean firstTxnReadOnly, boolean secondTxnReadOnly)
 			throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
-
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1559,22 +1397,12 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 				shutdown);
 
 		assertNotNull(db.startTransaction(firstTxnReadOnly));
-		try {
+		db.startTransaction(secondTxnReadOnly);
-			db.startTransaction(secondTxnReadOnly);
+		fail();
-			fail();
-		} finally {
-			context.assertIsSatisfied();
-		}
 	}
 
 	@Test
 	public void testCannotAddLocalIdentityAsContact() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
-
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1598,18 +1426,10 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testCannotAddDuplicateContact() throws Exception {
-		Mockery context = new Mockery();
-		@SuppressWarnings("unchecked")
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
-
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
@@ -1635,19 +1455,13 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		} finally {
 			db.endTransaction(transaction);
 		}
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	@SuppressWarnings("unchecked")
 	public void testMessageDependencies() throws Exception {
-		final int shutdownHandle = 12345;
+		int shutdownHandle = 12345;
-		Mockery context = new Mockery();
+		MessageId messageId2 = new MessageId(TestUtils.getRandomId());
-		final Database<Object> database = context.mock(Database.class);
-		final ShutdownManager shutdown = context.mock(ShutdownManager.class);
-		final EventBus eventBus = context.mock(EventBus.class);
-		final MessageId messageId2 = new MessageId(TestUtils.getRandomId());
 		context.checking(new Expectations() {{
 			// open()
 			oneOf(database).open();
@@ -1692,7 +1506,6 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 			// endTransaction()
 			oneOf(database).commitTransaction(txn);
 			// close()
-			oneOf(shutdown).removeShutdownHook(shutdownHandle);
 			oneOf(database).close();
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
@@ -1702,7 +1515,7 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 		Transaction transaction = db.startTransaction(false);
 		try {
 			db.addLocalMessage(transaction, message, metadata, true);
-			Collection<MessageId> dependencies = new ArrayList<MessageId>(2);
+			Collection<MessageId> dependencies = new ArrayList<>(2);
 			dependencies.add(messageId1);
 			dependencies.add(messageId2);
 			db.addMessageDependencies(transaction, message, dependencies);
@@ -1713,7 +1526,5 @@ public class DatabaseComponentImplTest extends BrambleTestCase {
 			db.endTransaction(transaction);
 		}
 		db.close();
-
-		context.assertIsSatisfied();
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseMigrationTest.java

@@ -0,0 +1,233 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DataTooNewException;
+import org.briarproject.bramble.api.db.DataTooOldException;
+import org.briarproject.bramble.api.db.DatabaseConfig;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.system.SystemClock;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.TestDatabaseConfig;
+import org.briarproject.bramble.test.TestUtils;
+import org.jmock.Expectations;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.sql.Connection;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.db.DatabaseConstants.DB_SETTINGS_NAMESPACE;
+import static org.briarproject.bramble.db.DatabaseConstants.SCHEMA_VERSION_KEY;
+import static org.briarproject.bramble.db.JdbcDatabase.CODE_SCHEMA_VERSION;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+@NotNullByDefault
+public abstract class DatabaseMigrationTest extends BrambleMockTestCase {
+
+	private final File testDir = TestUtils.getTestDirectory();
+	@SuppressWarnings("unchecked")
+	private final Migration<Connection> migration =
+			context.mock(Migration.class, "migration");
+	@SuppressWarnings("unchecked")
+	private final Migration<Connection> migration1 =
+			context.mock(Migration.class, "migration1");
+
+	protected final DatabaseConfig config =
+			new TestDatabaseConfig(testDir, 1024 * 1024);
+	protected final Clock clock = new SystemClock();
+
+	abstract Database<Connection> createDatabase(
+			List<Migration<Connection>> migrations) throws Exception;
+
+	@Before
+	public void setUp() {
+		assertTrue(testDir.mkdirs());
+	}
+
+	@After
+	public void tearDown() {
+		TestUtils.deleteTestDirectory(testDir);
+	}
+
+	@Test
+	public void testDoesNotRunMigrationsWhenCreatingDatabase()
+			throws Exception {
+		Database<Connection> db = createDatabase(singletonList(migration));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+	}
+
+	@Test(expected = DbException.class)
+	public void testThrowsExceptionIfDataSchemaVersionIsMissing()
+			throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(asList(migration, migration1));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, -1);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(asList(migration, migration1));
+		db.open();
+	}
+
+	@Test
+	public void testDoesNotRunMigrationsIfSchemaVersionsMatch()
+			throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(asList(migration, migration1));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+		// Reopen the DB - migrations should not be run
+		db = createDatabase(asList(migration, migration1));
+		assertTrue(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+	}
+
+	@Test(expected = DataTooNewException.class)
+	public void testThrowsExceptionIfDataIsNewerThanCode() throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(asList(migration, migration1));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION + 1);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(asList(migration, migration1));
+		db.open();
+	}
+
+	@Test(expected = DataTooOldException.class)
+	public void testThrowsExceptionIfCodeIsNewerThanDataAndNoMigrations()
+			throws Exception {
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(emptyList());
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION - 1);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(emptyList());
+		db.open();
+	}
+
+	@Test(expected = DataTooOldException.class)
+	public void testThrowsExceptionIfCodeIsNewerThanDataAndNoSuitableMigration()
+			throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(migration).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 2));
+			oneOf(migration).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 1));
+			oneOf(migration1).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 1));
+			oneOf(migration1).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION));
+		}});
+
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(asList(migration, migration1));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION - 3);
+		db.close();
+		// Reopen the DB - an exception should be thrown
+		db = createDatabase(asList(migration, migration1));
+		db.open();
+	}
+
+	@Test
+	public void testRunsMigrationIfCodeIsNewerThanDataAndSuitableMigration()
+			throws Exception {
+		context.checking(new Expectations() {{
+			// First migration should be run, increasing schema version by 2
+			oneOf(migration).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 2));
+			oneOf(migration).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION));
+			oneOf(migration).migrate(with(any(Connection.class)));
+			// Second migration is not suitable and should be skipped
+			oneOf(migration1).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 1));
+			oneOf(migration1).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION));
+		}});
+
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(asList(migration, migration1));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION - 2);
+		db.close();
+		// Reopen the DB - the first migration should be run
+		db = createDatabase(asList(migration, migration1));
+		assertTrue(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+	}
+
+	@Test
+	public void testRunsMigrationsIfCodeIsNewerThanDataAndSuitableMigrations()
+			throws Exception {
+		context.checking(new Expectations() {{
+			// First migration should be run, incrementing schema version
+			oneOf(migration).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 2));
+			oneOf(migration).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 1));
+			oneOf(migration).migrate(with(any(Connection.class)));
+			// Second migration should be run, incrementing schema version again
+			oneOf(migration1).getStartVersion();
+			will(returnValue(CODE_SCHEMA_VERSION - 1));
+			oneOf(migration1).getEndVersion();
+			will(returnValue(CODE_SCHEMA_VERSION));
+			oneOf(migration1).migrate(with(any(Connection.class)));
+		}});
+
+		// Open the DB for the first time
+		Database<Connection> db = createDatabase(asList(migration, migration1));
+		assertFalse(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		// Override the data schema version
+		setDataSchemaVersion(db, CODE_SCHEMA_VERSION - 2);
+		db.close();
+		// Reopen the DB - both migrations should be run
+		db = createDatabase(asList(migration, migration1));
+		assertTrue(db.open());
+		assertEquals(CODE_SCHEMA_VERSION, getDataSchemaVersion(db));
+		db.close();
+	}
+
+	private int getDataSchemaVersion(Database<Connection> db)
+			throws Exception {
+		Connection txn = db.startTransaction();
+		Settings s = db.getSettings(txn, DB_SETTINGS_NAMESPACE);
+		db.commitTransaction(txn);
+		return s.getInt(SCHEMA_VERSION_KEY, -1);
+	}
+
+	private void setDataSchemaVersion(Database<Connection> db, int version)
+			throws Exception {
+		Settings s = new Settings();
+		s.putInt(SCHEMA_VERSION_KEY, version);
+		Connection txn = db.startTransaction();
+		db.mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
+		db.commitTransaction(txn);
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/db/H2DatabaseTest.java

@@ -24,6 +24,7 @@ import org.briarproject.bramble.system.SystemClock;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestDatabaseConfig;
 import org.briarproject.bramble.test.TestUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -84,7 +85,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 	public H2DatabaseTest() throws Exception {
 		groupId = new GroupId(TestUtils.getRandomId());
-		clientId = new ClientId(TestUtils.getRandomString(5));
+		clientId = new ClientId(StringUtils.getRandomString(5));
 		byte[] descriptor = new byte[MAX_GROUP_DESCRIPTOR_LENGTH];
 		group = new Group(groupId, clientId, descriptor);
 		AuthorId authorId = new AuthorId(TestUtils.getRandomId());
@@ -463,28 +464,25 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 	@Test
 	public void testCloseWaitsForCommit() throws Exception {
-		final CountDownLatch closing = new CountDownLatch(1);
+		CountDownLatch closing = new CountDownLatch(1);
-		final CountDownLatch closed = new CountDownLatch(1);
+		CountDownLatch closed = new CountDownLatch(1);
-		final AtomicBoolean transactionFinished = new AtomicBoolean(false);
+		AtomicBoolean transactionFinished = new AtomicBoolean(false);
-		final AtomicBoolean error = new AtomicBoolean(false);
+		AtomicBoolean error = new AtomicBoolean(false);
-		final Database<Connection> db = open(false);
+		Database<Connection> db = open(false);
 
 		// Start a transaction
 		Connection txn = db.startTransaction();
 		// In another thread, close the database
-		Thread close = new Thread() {
+		Thread close = new Thread(() -> {
-			@Override
+			try {
-			public void run() {
+				closing.countDown();
-				try {
+				db.close();
-					closing.countDown();
+				if (!transactionFinished.get()) error.set(true);
-					db.close();
+				closed.countDown();
-					if (!transactionFinished.get()) error.set(true);
+			} catch (Exception e) {
-					closed.countDown();
+				error.set(true);
-				} catch (Exception e) {
-					error.set(true);
-				}
 			}
-		};
+		});
 		close.start();
 		closing.await();
 		// Do whatever the transaction needs to do
@@ -500,28 +498,25 @@ public class H2DatabaseTest extends BrambleTestCase {
 
 	@Test
 	public void testCloseWaitsForAbort() throws Exception {
-		final CountDownLatch closing = new CountDownLatch(1);
+		CountDownLatch closing = new CountDownLatch(1);
-		final CountDownLatch closed = new CountDownLatch(1);
+		CountDownLatch closed = new CountDownLatch(1);
-		final AtomicBoolean transactionFinished = new AtomicBoolean(false);
+		AtomicBoolean transactionFinished = new AtomicBoolean(false);
-		final AtomicBoolean error = new AtomicBoolean(false);
+		AtomicBoolean error = new AtomicBoolean(false);
-		final Database<Connection> db = open(false);
+		Database<Connection> db = open(false);
 
 		// Start a transaction
 		Connection txn = db.startTransaction();
 		// In another thread, close the database
-		Thread close = new Thread() {
+		Thread close = new Thread(() -> {
-			@Override
+			try {
-			public void run() {
+				closing.countDown();
-				try {
+				db.close();
-					closing.countDown();
+				if (!transactionFinished.get()) error.set(true);
-					db.close();
+				closed.countDown();
-					if (!transactionFinished.get()) error.set(true);
+			} catch (Exception e) {
-					closed.countDown();
+				error.set(true);
-				} catch (Exception e) {
-					error.set(true);
-				}
 			}
-		};
+		});
 		close.start();
 		closing.await();
 		// Do whatever the transaction needs to do
@@ -869,7 +864,7 @@ public class H2DatabaseTest extends BrambleTestCase {
 		assertEquals(0, db.countOfferedMessages(txn, contactId));
 
 		// Add some offered messages and count them
-		List<MessageId> ids = new ArrayList<MessageId>();
+		List<MessageId> ids = new ArrayList<>();
 		for (int i = 0; i < 10; i++) {
 			MessageId m = new MessageId(TestUtils.getRandomId());
 			db.addOfferedMessage(txn, contactId, m);

bramble-core/src/test/java/org/briarproject/bramble/db/H2MigrationTest.java

@@ -0,0 +1,21 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.sql.Connection;
+import java.util.List;
+
+@NotNullByDefault
+public class H2MigrationTest extends DatabaseMigrationTest {
+
+	@Override
+	Database<Connection> createDatabase(List<Migration<Connection>> migrations)
+			throws Exception {
+		return new H2Database(config, clock) {
+			@Override
+			List<Migration<Connection>> getMigrations() {
+				return migrations;
+			}
+		};
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/db/LockFairnessTest.java

@@ -17,56 +17,50 @@ public class LockFairnessTest extends BrambleTestCase {
 	@Test
 	public void testReadersCanShareTheLock() throws Exception {
 		// Use a fair lock
-		final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+		ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
-		final CountDownLatch firstReaderHasLock = new CountDownLatch(1);
+		CountDownLatch firstReaderHasLock = new CountDownLatch(1);
-		final CountDownLatch firstReaderHasFinished = new CountDownLatch(1);
+		CountDownLatch firstReaderHasFinished = new CountDownLatch(1);
-		final CountDownLatch secondReaderHasLock = new CountDownLatch(1);
+		CountDownLatch secondReaderHasLock = new CountDownLatch(1);
-		final CountDownLatch secondReaderHasFinished = new CountDownLatch(1);
+		CountDownLatch secondReaderHasFinished = new CountDownLatch(1);
 		// First reader
-		Thread first = new Thread() {
+		Thread first = new Thread(() -> {
-			@Override
+			try {
-			public void run() {
+				// Acquire the lock
+				lock.readLock().lock();
 				try {
-					// Acquire the lock
+					// Allow the second reader to acquire the lock
-					lock.readLock().lock();
+					firstReaderHasLock.countDown();
-					try {
+					// Wait for the second reader to acquire the lock
-						// Allow the second reader to acquire the lock
+					assertTrue(secondReaderHasLock.await(10, SECONDS));
-						firstReaderHasLock.countDown();
+				} finally {
-						// Wait for the second reader to acquire the lock
+					// Release the lock
-						assertTrue(secondReaderHasLock.await(10, SECONDS));
+					lock.readLock().unlock();
-					} finally {
-						// Release the lock
-						lock.readLock().unlock();
-					}
-				} catch (InterruptedException e) {
-					fail();
 				}
-				firstReaderHasFinished.countDown();
+			} catch (InterruptedException e) {
+				fail();
 			}
-		};
+			firstReaderHasFinished.countDown();
+		});
 		first.start();
 		// Second reader
-		Thread second = new Thread() {
+		Thread second = new Thread(() -> {
-			@Override
+			try {
-			public void run() {
+				// Wait for the first reader to acquire the lock
+				assertTrue(firstReaderHasLock.await(10, SECONDS));
+				// Acquire the lock
+				lock.readLock().lock();
 				try {
-					// Wait for the first reader to acquire the lock
+					// Allow the first reader to release the lock
-					assertTrue(firstReaderHasLock.await(10, SECONDS));
+					secondReaderHasLock.countDown();
-					// Acquire the lock
+				} finally {
-					lock.readLock().lock();
+					// Release the lock
-					try {
+					lock.readLock().unlock();
-						// Allow the first reader to release the lock
-						secondReaderHasLock.countDown();
-					} finally {
-						// Release the lock
-						lock.readLock().unlock();
-					}
-				} catch (InterruptedException e) {
-					fail();
 				}
-				secondReaderHasFinished.countDown();
+			} catch (InterruptedException e) {
+				fail();
 			}
-		};
+			secondReaderHasFinished.countDown();
+		});
 		second.start();
 		// Wait for both readers to finish
 		assertTrue(firstReaderHasFinished.await(10, SECONDS));
@@ -76,86 +70,77 @@ public class LockFairnessTest extends BrambleTestCase {
 	@Test
 	public void testWritersDoNotStarve() throws Exception {
 		// Use a fair lock
-		final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+		ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
-		final CountDownLatch firstReaderHasLock = new CountDownLatch(1);
+		CountDownLatch firstReaderHasLock = new CountDownLatch(1);
-		final CountDownLatch firstReaderHasFinished = new CountDownLatch(1);
+		CountDownLatch firstReaderHasFinished = new CountDownLatch(1);
-		final CountDownLatch secondReaderHasFinished = new CountDownLatch(1);
+		CountDownLatch secondReaderHasFinished = new CountDownLatch(1);
-		final CountDownLatch writerHasFinished = new CountDownLatch(1);
+		CountDownLatch writerHasFinished = new CountDownLatch(1);
-		final AtomicBoolean secondReaderHasHeldLock = new AtomicBoolean(false);
+		AtomicBoolean secondReaderHasHeldLock = new AtomicBoolean(false);
-		final AtomicBoolean writerHasHeldLock = new AtomicBoolean(false);
+		AtomicBoolean writerHasHeldLock = new AtomicBoolean(false);
 		// First reader
-		Thread first = new Thread() {
+		Thread first = new Thread(() -> {
-			@Override
+			try {
-			public void run() {
+				// Acquire the lock
+				lock.readLock().lock();
 				try {
-					// Acquire the lock
+					// Allow the other threads to acquire the lock
-					lock.readLock().lock();
+					firstReaderHasLock.countDown();
-					try {
+					// Wait for both other threads to wait for the lock
-						// Allow the other threads to acquire the lock
+					while (lock.getQueueLength() < 2) Thread.sleep(10);
-						firstReaderHasLock.countDown();
+					// No other thread should have acquired the lock
-						// Wait for both other threads to wait for the lock
+					assertFalse(secondReaderHasHeldLock.get());
-						while (lock.getQueueLength() < 2) Thread.sleep(10);
+					assertFalse(writerHasHeldLock.get());
-						// No other thread should have acquired the lock
+				} finally {
-						assertFalse(secondReaderHasHeldLock.get());
+					// Release the lock
-						assertFalse(writerHasHeldLock.get());
+					lock.readLock().unlock();
-					} finally {
-						// Release the lock
-						lock.readLock().unlock();
-					}
-				} catch (InterruptedException e) {
-					fail();
 				}
-				firstReaderHasFinished.countDown();
+			} catch (InterruptedException e) {
+				fail();
 			}
-		};
+			firstReaderHasFinished.countDown();
+		});
 		first.start();
 		// Writer
-		Thread writer = new Thread() {
+		Thread writer = new Thread(() -> {
-			@Override
+			try {
-			public void run() {
+				// Wait for the first reader to acquire the lock
+				assertTrue(firstReaderHasLock.await(10, SECONDS));
+				// Acquire the lock
+				lock.writeLock().lock();
 				try {
-					// Wait for the first reader to acquire the lock
+					writerHasHeldLock.set(true);
-					assertTrue(firstReaderHasLock.await(10, SECONDS));
+					// The second reader should not overtake the writer
-					// Acquire the lock
+					assertFalse(secondReaderHasHeldLock.get());
-					lock.writeLock().lock();
+				} finally {
-					try {
+					lock.writeLock().unlock();
-						writerHasHeldLock.set(true);
-						// The second reader should not overtake the writer
-						assertFalse(secondReaderHasHeldLock.get());
-					} finally {
-						lock.writeLock().unlock();
-					}
-				} catch (InterruptedException e) {
-					fail();
 				}
-				writerHasFinished.countDown();
+			} catch (InterruptedException e) {
+				fail();
 			}
-		};
+			writerHasFinished.countDown();
+		});
 		writer.start();
 		// Second reader
-		Thread second = new Thread() {
+		Thread second = new Thread(() -> {
-			@Override
+			try {
-			public void run() {
+				// Wait for the first reader to acquire the lock
+				assertTrue(firstReaderHasLock.await(10, SECONDS));
+				// Wait for the writer to wait for the lock
+				while (lock.getQueueLength() < 1) Thread.sleep(10);
+				// Acquire the lock
+				lock.readLock().lock();
 				try {
-					// Wait for the first reader to acquire the lock
+					secondReaderHasHeldLock.set(true);
-					assertTrue(firstReaderHasLock.await(10, SECONDS));
+					// The second reader should not overtake the writer
-					// Wait for the writer to wait for the lock
+					assertTrue(writerHasHeldLock.get());
-					while (lock.getQueueLength() < 1) Thread.sleep(10);
+				} finally {
-					// Acquire the lock
+					lock.readLock().unlock();
-					lock.readLock().lock();
-					try {
-						secondReaderHasHeldLock.set(true);
-						// The second reader should not overtake the writer
-						assertTrue(writerHasHeldLock.get());
-					} finally {
-						lock.readLock().unlock();
-					}
-				} catch (InterruptedException e) {
-					fail();
 				}
-				secondReaderHasFinished.countDown();
+			} catch (InterruptedException e) {
+				fail();
 			}
-		};
+			secondReaderHasFinished.countDown();
+		});
 		second.start();
 		// Wait for all the threads to finish
 		assertTrue(firstReaderHasFinished.await(10, SECONDS));

bramble-core/src/test/java/org/briarproject/bramble/db/Migration30_31Test.java

@@ -0,0 +1,280 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.ValidationManager.State;
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.TestUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Map.Entry;
+
+import static junit.framework.TestCase.assertNotNull;
+import static junit.framework.TestCase.assertTrue;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.DELIVERED;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
+import static org.briarproject.bramble.test.TestUtils.getRandomId;
+import static org.briarproject.bramble.util.StringUtils.getRandomString;
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+public class Migration30_31Test extends BrambleTestCase {
+
+	private static final String CREATE_GROUPS_STUB =
+			"CREATE TABLE groups"
+					+ " (groupID BINARY(32) NOT NULL,"
+					+ " PRIMARY KEY (groupId))";
+
+	private static final String CREATE_MESSAGES =
+			"CREATE TABLE messages"
+					+ " (messageId BINARY(32) NOT NULL,"
+					+ " groupId BINARY(32) NOT NULL,"
+					+ " timestamp BIGINT NOT NULL,"
+					+ " state INT NOT NULL,"
+					+ " shared BOOLEAN NOT NULL,"
+					+ " length INT NOT NULL,"
+					+ " raw BLOB," // Null if message has been deleted
+					+ " PRIMARY KEY (messageId),"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
+					+ " ON DELETE CASCADE)";
+
+	private static final String CREATE_MESSAGE_METADATA_30 =
+			"CREATE TABLE messageMetadata"
+					+ " (messageId BINARY(32) NOT NULL,"
+					+ " key VARCHAR NOT NULL,"
+					+ " value BINARY NOT NULL,"
+					+ " PRIMARY KEY (messageId, key),"
+					+ " FOREIGN KEY (messageId)"
+					+ " REFERENCES messages (messageId)"
+					+ " ON DELETE CASCADE)";
+
+	private final File testDir = TestUtils.getTestDirectory();
+	private final File db = new File(testDir, "db");
+	private final String url = "jdbc:h2:" + db.getAbsolutePath();
+	private final GroupId groupId = new GroupId(getRandomId());
+	private final GroupId groupId1 = new GroupId(getRandomId());
+	private final Message message = TestUtils.getMessage(groupId);
+	private final Message message1 = TestUtils.getMessage(groupId1);
+	private final Metadata meta = new Metadata(), meta1 = new Metadata();
+
+	private Connection connection = null;
+
+	public Migration30_31Test() {
+		for (int i = 0; i < 10; i++) {
+			meta.put(getRandomString(123 + i), getRandomBytes(123 + i));
+			meta1.put(getRandomString(123 + i), getRandomBytes(123 + i));
+		}
+	}
+
+	@Before
+	public void setUp() throws Exception {
+		assertTrue(testDir.mkdirs());
+		Class.forName("org.h2.Driver");
+		connection = DriverManager.getConnection(url);
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		if (connection != null) connection.close();
+		TestUtils.deleteTestDirectory(testDir);
+	}
+
+	@Test
+	public void testMigration() throws Exception {
+		try {
+			Statement s = connection.createStatement();
+			s.execute(CREATE_GROUPS_STUB);
+			s.execute(CREATE_MESSAGES);
+			s.execute(CREATE_MESSAGE_METADATA_30);
+			s.close();
+
+			addGroup(groupId);
+			addMessage(message, DELIVERED, true);
+			addMessageMetadata30(message, meta);
+			assertMetadataEquals(meta, getMessageMetadata(message.getId()));
+
+			addGroup(groupId1);
+			addMessage(message1, UNKNOWN, false);
+			addMessageMetadata30(message1, meta1);
+			assertMetadataEquals(meta1, getMessageMetadata(message1.getId()));
+
+			new Migration30_31().migrate(connection);
+
+			assertMetadataEquals(meta, getMessageMetadata(message.getId()));
+			for (String key : meta.keySet()) {
+				GroupId g = getMessageMetadataGroupId31(message.getId(), key);
+				assertEquals(groupId, g);
+				State state = getMessageMetadataState31(message.getId(), key);
+				assertEquals(DELIVERED, state);
+			}
+
+			assertMetadataEquals(meta1, getMessageMetadata(message1.getId()));
+			for (String key : meta1.keySet()) {
+				GroupId g = getMessageMetadataGroupId31(message1.getId(), key);
+				assertEquals(groupId1, g);
+				State state = getMessageMetadataState31(message1.getId(), key);
+				assertEquals(UNKNOWN, state);
+			}
+		} catch (SQLException e) {
+			connection.close();
+			throw e;
+		}
+	}
+
+	private void addGroup(GroupId g) throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO groups (groupId) VALUES (?)";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, g.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private void addMessage(Message m, State state, boolean shared)
+			throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO messages (messageId, groupId, timestamp,"
+					+ " state, shared, length, raw)"
+					+ " VALUES (?, ?, ?, ?, ?, ?, ?)";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getId().getBytes());
+			ps.setBytes(2, m.getGroupId().getBytes());
+			ps.setLong(3, m.getTimestamp());
+			ps.setInt(4, state.getValue());
+			ps.setBoolean(5, shared);
+			byte[] raw = m.getRaw();
+			ps.setInt(6, raw.length);
+			ps.setBytes(7, raw);
+			int affected = ps.executeUpdate();
+			if (affected != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private void addMessageMetadata30(Message m, Metadata meta)
+			throws SQLException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "INSERT INTO messageMetadata"
+					+ " (messageId, key, value)"
+					+ " VALUES (?, ?, ?)";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getId().getBytes());
+			for (Entry<String, byte[]> e : meta.entrySet()) {
+				ps.setString(2, e.getKey());
+				ps.setBytes(3, e.getValue());
+				ps.addBatch();
+			}
+			int[] batchAffected = ps.executeBatch();
+			if (batchAffected.length != meta.size())
+				throw new DbStateException();
+			for (int rows : batchAffected)
+				if (rows != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private Metadata getMessageMetadata(MessageId m) throws SQLException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT key, value FROM messageMetadata"
+					+ " WHERE messageId = ?";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			rs = ps.executeQuery();
+			Metadata meta = new Metadata();
+			while (rs.next()) meta.put(rs.getString(1), rs.getBytes(2));
+			rs.close();
+			ps.close();
+			return meta;
+		} catch (SQLException e) {
+			if (rs != null) rs.close();
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private GroupId getMessageMetadataGroupId31(MessageId m, String key)
+		throws SQLException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT groupId FROM messageMetadata"
+					+ " WHERE messageId = ? AND key = ?";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setString(2, key);
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			GroupId g = new GroupId(rs.getBytes(1));
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return g;
+		} catch (SQLException e) {
+			if (rs != null) rs.close();
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private State getMessageMetadataState31(MessageId m, String key)
+		throws SQLException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT state FROM messageMetadata"
+					+ " WHERE messageId = ? AND key = ?";
+			ps = connection.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setString(2, key);
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			State state = State.fromValue(rs.getInt(1));
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return state;
+		} catch (SQLException e) {
+			if (rs != null) rs.close();
+			if (ps != null) ps.close();
+			throw e;
+		}
+	}
+
+	private void assertMetadataEquals(Metadata expected, Metadata actual) {
+		assertEquals(expected.size(), actual.size());
+		for (Entry<String, byte[]> e : expected.entrySet()) {
+			byte[] value = actual.get(e.getKey());
+			assertNotNull(value);
+			assertArrayEquals(e.getValue(), value);
+		}
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/identity/IdentityManagerImplTest.java

@@ -11,6 +11,7 @@ import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.TestUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.jmock.Expectations;
 import org.junit.Test;
 
@@ -31,8 +32,9 @@ public class IdentityManagerImplTest extends BrambleMockTestCase {
 	private final Transaction txn = new Transaction(null, false);
 	private final LocalAuthor localAuthor =
 			new LocalAuthor(new AuthorId(TestUtils.getRandomId()),
-					TestUtils.getRandomString(8), TestUtils.getRandomBytes(42),
+					StringUtils.getRandomString(8),
-					TestUtils.getRandomBytes(42), 0);
+					TestUtils.getRandomBytes(42), TestUtils.getRandomBytes(42),
+					0);
 	private final Collection<LocalAuthor> localAuthors =
 			Collections.singletonList(localAuthor);
 
@@ -78,8 +80,8 @@ public class IdentityManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testGetAuthorStatus() throws DbException {
-		final AuthorId authorId = new AuthorId(TestUtils.getRandomId());
+		AuthorId authorId = new AuthorId(TestUtils.getRandomId());
-		final Collection<Contact> contacts = new ArrayList<Contact>();
+		Collection<Contact> contacts = new ArrayList<>();
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -93,7 +95,7 @@ public class IdentityManagerImplTest extends BrambleMockTestCase {
 		assertEquals(UNKNOWN, identityManager.getAuthorStatus(authorId));
 
 		// add one unverified contact
-		Author author = new Author(authorId, TestUtils.getRandomString(8),
+		Author author = new Author(authorId, StringUtils.getRandomString(8),
 				TestUtils.getRandomBytes(42));
 		Contact contact =
 				new Contact(new ContactId(1), author, localAuthor.getId(),
@@ -123,8 +125,8 @@ public class IdentityManagerImplTest extends BrambleMockTestCase {
 				identityManager.getAuthorStatus(localAuthor.getId()));
 	}
 
-	private void checkAuthorStatusContext(final AuthorId authorId,
+	private void checkAuthorStatusContext(AuthorId authorId,
-			final Collection<Contact> contacts) throws DbException {
+			Collection<Contact> contacts) throws DbException {
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));

bramble-core/src/test/java/org/briarproject/bramble/keyagreement/KeyAgreementProtocolTest.java

@@ -65,11 +65,11 @@ public class KeyAgreementProtocolTest extends BrambleTestCase {
 	@Test
 	public void testAliceProtocol() throws Exception {
 		// set up
-		final Payload theirPayload = new Payload(BOB_COMMIT, null);
+		Payload theirPayload = new Payload(BOB_COMMIT, null);
-		final Payload ourPayload = new Payload(ALICE_COMMIT, null);
+		Payload ourPayload = new Payload(ALICE_COMMIT, null);
-		final KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
+		KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
-		final SecretKey sharedSecret = TestUtils.getSecretKey();
+		SecretKey sharedSecret = TestUtils.getSecretKey();
-		final SecretKey masterSecret = TestUtils.getSecretKey();
+		SecretKey masterSecret = TestUtils.getSecretKey();
 
 		KeyAgreementProtocol protocol =
 				new KeyAgreementProtocol(callbacks, crypto, payloadEncoder,
@@ -129,11 +129,11 @@ public class KeyAgreementProtocolTest extends BrambleTestCase {
 	@Test
 	public void testBobProtocol() throws Exception {
 		// set up
-		final Payload theirPayload = new Payload(ALICE_COMMIT, null);
+		Payload theirPayload = new Payload(ALICE_COMMIT, null);
-		final Payload ourPayload = new Payload(BOB_COMMIT, null);
+		Payload ourPayload = new Payload(BOB_COMMIT, null);
-		final KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
+		KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
-		final SecretKey sharedSecret = TestUtils.getSecretKey();
+		SecretKey sharedSecret = TestUtils.getSecretKey();
-		final SecretKey masterSecret = TestUtils.getSecretKey();
+		SecretKey masterSecret = TestUtils.getSecretKey();
 
 		KeyAgreementProtocol protocol =
 				new KeyAgreementProtocol(callbacks, crypto, payloadEncoder,
@@ -192,9 +192,9 @@ public class KeyAgreementProtocolTest extends BrambleTestCase {
 	@Test(expected = AbortException.class)
 	public void testAliceProtocolAbortOnBadKey() throws Exception {
 		// set up
-		final Payload theirPayload = new Payload(BOB_COMMIT, null);
+		Payload theirPayload = new Payload(BOB_COMMIT, null);
-		final Payload ourPayload = new Payload(ALICE_COMMIT, null);
+		Payload ourPayload = new Payload(ALICE_COMMIT, null);
-		final KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
+		KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
 
 		KeyAgreementProtocol protocol =
 				new KeyAgreementProtocol(callbacks, crypto, payloadEncoder,
@@ -233,9 +233,9 @@ public class KeyAgreementProtocolTest extends BrambleTestCase {
 	@Test(expected = AbortException.class)
 	public void testBobProtocolAbortOnBadKey() throws Exception {
 		// set up
-		final Payload theirPayload = new Payload(ALICE_COMMIT, null);
+		Payload theirPayload = new Payload(ALICE_COMMIT, null);
-		final Payload ourPayload = new Payload(BOB_COMMIT, null);
+		Payload ourPayload = new Payload(BOB_COMMIT, null);
-		final KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
+		KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
 
 		KeyAgreementProtocol protocol =
 				new KeyAgreementProtocol(callbacks, crypto, payloadEncoder,
@@ -270,10 +270,10 @@ public class KeyAgreementProtocolTest extends BrambleTestCase {
 	@Test(expected = AbortException.class)
 	public void testAliceProtocolAbortOnBadConfirm() throws Exception {
 		// set up
-		final Payload theirPayload = new Payload(BOB_COMMIT, null);
+		Payload theirPayload = new Payload(BOB_COMMIT, null);
-		final Payload ourPayload = new Payload(ALICE_COMMIT, null);
+		Payload ourPayload = new Payload(ALICE_COMMIT, null);
-		final KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
+		KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
-		final SecretKey sharedSecret = TestUtils.getSecretKey();
+		SecretKey sharedSecret = TestUtils.getSecretKey();
 
 		KeyAgreementProtocol protocol =
 				new KeyAgreementProtocol(callbacks, crypto, payloadEncoder,
@@ -335,10 +335,10 @@ public class KeyAgreementProtocolTest extends BrambleTestCase {
 	@Test(expected = AbortException.class)
 	public void testBobProtocolAbortOnBadConfirm() throws Exception {
 		// set up
-		final Payload theirPayload = new Payload(ALICE_COMMIT, null);
+		Payload theirPayload = new Payload(ALICE_COMMIT, null);
-		final Payload ourPayload = new Payload(BOB_COMMIT, null);
+		Payload ourPayload = new Payload(BOB_COMMIT, null);
-		final KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
+		KeyPair ourKeyPair = new KeyPair(ourPubKey, null);
-		final SecretKey sharedSecret = TestUtils.getSecretKey();
+		SecretKey sharedSecret = TestUtils.getSecretKey();
 
 		KeyAgreementProtocol protocol =
 				new KeyAgreementProtocol(callbacks, crypto, payloadEncoder,

bramble-core/src/test/java/org/briarproject/bramble/lifecycle/ShutdownManagerImplTest.java

@@ -15,13 +15,9 @@ public class ShutdownManagerImplTest extends BrambleTestCase {
 	@Test
 	public void testAddAndRemove() {
 		ShutdownManager s = createShutdownManager();
-		Set<Integer> handles = new HashSet<Integer>();
+		Set<Integer> handles = new HashSet<>();
 		for (int i = 0; i < 100; i++) {
-			int handle = s.addShutdownHook(new Runnable() {
+			int handle = s.addShutdownHook(() -> {});
-				@Override
-				public void run() {
-				}
-			});
 			// The handles should all be distinct
 			assertTrue(handles.add(handle));
 		}

bramble-core/src/test/java/org/briarproject/bramble/plugin/ConnectionRegistryImplTest.java

@@ -35,7 +35,7 @@ public class ConnectionRegistryImplTest extends BrambleTestCase {
 	@Test
 	public void testRegisterAndUnregister() {
 		Mockery context = new Mockery();
-		final EventBus eventBus = context.mock(EventBus.class);
+		EventBus eventBus = context.mock(EventBus.class);
 		context.checking(new Expectations() {{
 			exactly(5).of(eventBus).broadcast(with(any(
 					ConnectionOpenedEvent.class)));

bramble-core/src/test/java/org/briarproject/bramble/plugin/PluginManagerImplTest.java

@@ -30,36 +30,36 @@ public class PluginManagerImplTest extends BrambleTestCase {
 		Mockery context = new Mockery() {{
 			setThreadingPolicy(new Synchroniser());
 		}};
-		final Executor ioExecutor = Executors.newSingleThreadExecutor();
+		Executor ioExecutor = Executors.newSingleThreadExecutor();
-		final EventBus eventBus = context.mock(EventBus.class);
+		EventBus eventBus = context.mock(EventBus.class);
-		final PluginConfig pluginConfig = context.mock(PluginConfig.class);
+		PluginConfig pluginConfig = context.mock(PluginConfig.class);
-		final ConnectionManager connectionManager =
+		ConnectionManager connectionManager =
 				context.mock(ConnectionManager.class);
-		final SettingsManager settingsManager =
+		SettingsManager settingsManager =
 				context.mock(SettingsManager.class);
-		final TransportPropertyManager transportPropertyManager =
+		TransportPropertyManager transportPropertyManager =
 				context.mock(TransportPropertyManager.class);
-		final UiCallback uiCallback = context.mock(UiCallback.class);
+		UiCallback uiCallback = context.mock(UiCallback.class);
 
 		// Two simplex plugin factories: both create plugins, one fails to start
-		final SimplexPluginFactory simplexFactory =
+		SimplexPluginFactory simplexFactory =
 				context.mock(SimplexPluginFactory.class);
-		final SimplexPlugin simplexPlugin = context.mock(SimplexPlugin.class);
+		SimplexPlugin simplexPlugin = context.mock(SimplexPlugin.class);
-		final TransportId simplexId = new TransportId("simplex");
+		TransportId simplexId = new TransportId("simplex");
-		final SimplexPluginFactory simplexFailFactory =
+		SimplexPluginFactory simplexFailFactory =
 				context.mock(SimplexPluginFactory.class, "simplexFailFactory");
-		final SimplexPlugin simplexFailPlugin =
+		SimplexPlugin simplexFailPlugin =
 				context.mock(SimplexPlugin.class, "simplexFailPlugin");
-		final TransportId simplexFailId = new TransportId("simplex1");
+		TransportId simplexFailId = new TransportId("simplex1");
 
 		// Two duplex plugin factories: one creates a plugin, the other fails
-		final DuplexPluginFactory duplexFactory =
+		DuplexPluginFactory duplexFactory =
 				context.mock(DuplexPluginFactory.class);
-		final DuplexPlugin duplexPlugin = context.mock(DuplexPlugin.class);
+		DuplexPlugin duplexPlugin = context.mock(DuplexPlugin.class);
-		final TransportId duplexId = new TransportId("duplex");
+		TransportId duplexId = new TransportId("duplex");
-		final DuplexPluginFactory duplexFailFactory =
+		DuplexPluginFactory duplexFailFactory =
 				context.mock(DuplexPluginFactory.class, "duplexFailFactory");
-		final TransportId duplexFailId = new TransportId("duplex1");
+		TransportId duplexFailId = new TransportId("duplex1");
 
 		context.checking(new Expectations() {{
 			allowing(simplexPlugin).getId();

bramble-core/src/test/java/org/briarproject/bramble/plugin/PollerTest.java

@@ -12,14 +12,14 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
 import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.ImmediateExecutor;
 import org.briarproject.bramble.test.RunAction;
 import org.jmock.Expectations;
-import org.jmock.Mockery;
 import org.jmock.lib.legacy.ClassImposteriser;
 import org.junit.Test;
 
@@ -29,48 +29,55 @@ import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
 
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
-public class PollerTest extends BrambleTestCase {
+public class PollerTest extends BrambleMockTestCase {
 
+	private final ScheduledExecutorService scheduler =
+			context.mock(ScheduledExecutorService.class);
+	private final ConnectionManager connectionManager =
+			context.mock(ConnectionManager.class);
+	private final ConnectionRegistry connectionRegistry =
+			context.mock(ConnectionRegistry.class);
+	private final PluginManager pluginManager =
+			context.mock(PluginManager.class);
+	private final Clock clock = context.mock(Clock.class);
+	private final ScheduledFuture future = context.mock(ScheduledFuture.class);
+	private final SecureRandom random;
+
+	private final Executor ioExecutor = new ImmediateExecutor();
+	private final TransportId transportId = new TransportId("id");
 	private final ContactId contactId = new ContactId(234);
 	private final int pollingInterval = 60 * 1000;
 	private final long now = System.currentTimeMillis();
 
+	public PollerTest() {
+		context.setImposteriser(ClassImposteriser.INSTANCE);
+		random = context.mock(SecureRandom.class);
+	}
+
 	@Test
 	public void testConnectOnContactStatusChanged() throws Exception {
-		Mockery context = new Mockery();
-		context.setImposteriser(ClassImposteriser.INSTANCE);
-		final Executor ioExecutor = new ImmediateExecutor();
-		final ScheduledExecutorService scheduler =
-				context.mock(ScheduledExecutorService.class);
-		final ConnectionManager connectionManager =
-				context.mock(ConnectionManager.class);
-		final ConnectionRegistry connectionRegistry =
-				context.mock(ConnectionRegistry.class);
-		final PluginManager pluginManager = context.mock(PluginManager.class);
-		final SecureRandom random = context.mock(SecureRandom.class);
-		final Clock clock = context.mock(Clock.class);
-
 		// Two simplex plugins: one supports polling, the other doesn't
-		final SimplexPlugin simplexPlugin = context.mock(SimplexPlugin.class);
+		SimplexPlugin simplexPlugin = context.mock(SimplexPlugin.class);
-		final SimplexPlugin simplexPlugin1 =
+		SimplexPlugin simplexPlugin1 =
 				context.mock(SimplexPlugin.class, "simplexPlugin1");
-		final TransportId simplexId1 = new TransportId("simplex1");
+		TransportId simplexId1 = new TransportId("simplex1");
-		final List<SimplexPlugin> simplexPlugins = Arrays.asList(simplexPlugin,
+		List<SimplexPlugin> simplexPlugins = Arrays.asList(simplexPlugin,
 				simplexPlugin1);
-		final TransportConnectionWriter simplexWriter =
+		TransportConnectionWriter simplexWriter =
 				context.mock(TransportConnectionWriter.class);
 
 		// Two duplex plugins: one supports polling, the other doesn't
-		final DuplexPlugin duplexPlugin = context.mock(DuplexPlugin.class);
+		DuplexPlugin duplexPlugin = context.mock(DuplexPlugin.class);
-		final TransportId duplexId = new TransportId("duplex");
+		TransportId duplexId = new TransportId("duplex");
-		final DuplexPlugin duplexPlugin1 =
+		DuplexPlugin duplexPlugin1 =
 				context.mock(DuplexPlugin.class, "duplexPlugin1");
-		final List<DuplexPlugin> duplexPlugins = Arrays.asList(duplexPlugin,
+		List<DuplexPlugin> duplexPlugins = Arrays.asList(duplexPlugin,
 				duplexPlugin1);
-		final DuplexTransportConnection duplexConnection =
+		DuplexTransportConnection duplexConnection =
 				context.mock(DuplexTransportConnection.class);
 
 		context.checking(new Expectations() {{
@@ -120,29 +127,13 @@ public class PollerTest extends BrambleTestCase {
 				connectionRegistry, pluginManager, random, clock);
 
 		p.eventOccurred(new ContactStatusChangedEvent(contactId, true));
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testRescheduleAndReconnectOnConnectionClosed()
 			throws Exception {
-		Mockery context = new Mockery();
+		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
-		context.setImposteriser(ClassImposteriser.INSTANCE);
+		DuplexTransportConnection duplexConnection =
-		final Executor ioExecutor = new ImmediateExecutor();
-		final ScheduledExecutorService scheduler =
-				context.mock(ScheduledExecutorService.class);
-		final ConnectionManager connectionManager =
-				context.mock(ConnectionManager.class);
-		final ConnectionRegistry connectionRegistry =
-				context.mock(ConnectionRegistry.class);
-		final PluginManager pluginManager = context.mock(PluginManager.class);
-		final SecureRandom random = context.mock(SecureRandom.class);
-		final Clock clock = context.mock(Clock.class);
-
-		final DuplexPlugin plugin = context.mock(DuplexPlugin.class);
-		final TransportId transportId = new TransportId("id");
-		final DuplexTransportConnection duplexConnection =
 				context.mock(DuplexTransportConnection.class);
 
 		context.checking(new Expectations() {{
@@ -168,6 +159,7 @@ public class PollerTest extends BrambleTestCase {
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
 					with((long) pollingInterval), with(MILLISECONDS));
+			will(returnValue(future));
 			// connectToContact()
 			// Check whether the contact is already connected
 			oneOf(connectionRegistry).isConnected(contactId, transportId);
@@ -185,28 +177,12 @@ public class PollerTest extends BrambleTestCase {
 
 		p.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
 				false));
-
-		context.assertIsSatisfied();
 	}
 
 
 	@Test
 	public void testRescheduleOnConnectionOpened() throws Exception {
-		Mockery context = new Mockery();
+		Plugin plugin = context.mock(Plugin.class);
-		context.setImposteriser(ClassImposteriser.INSTANCE);
-		final Executor ioExecutor = new ImmediateExecutor();
-		final ScheduledExecutorService scheduler =
-				context.mock(ScheduledExecutorService.class);
-		final ConnectionManager connectionManager =
-				context.mock(ConnectionManager.class);
-		final ConnectionRegistry connectionRegistry =
-				context.mock(ConnectionRegistry.class);
-		final PluginManager pluginManager = context.mock(PluginManager.class);
-		final SecureRandom random = context.mock(SecureRandom.class);
-		final Clock clock = context.mock(Clock.class);
-
-		final DuplexPlugin plugin = context.mock(DuplexPlugin.class);
-		final TransportId transportId = new TransportId("id");
 
 		context.checking(new Expectations() {{
 			allowing(plugin).getId();
@@ -224,6 +200,7 @@ public class PollerTest extends BrambleTestCase {
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
 					with((long) pollingInterval), with(MILLISECONDS));
+			will(returnValue(future));
 		}});
 
 		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
@@ -231,27 +208,11 @@ public class PollerTest extends BrambleTestCase {
 
 		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
 				false));
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
 	public void testRescheduleDoesNotReplaceEarlierTask() throws Exception {
-		Mockery context = new Mockery();
+		Plugin plugin = context.mock(Plugin.class);
-		context.setImposteriser(ClassImposteriser.INSTANCE);
-		final Executor ioExecutor = new ImmediateExecutor();
-		final ScheduledExecutorService scheduler =
-				context.mock(ScheduledExecutorService.class);
-		final ConnectionManager connectionManager =
-				context.mock(ConnectionManager.class);
-		final ConnectionRegistry connectionRegistry =
-				context.mock(ConnectionRegistry.class);
-		final PluginManager pluginManager = context.mock(PluginManager.class);
-		final SecureRandom random = context.mock(SecureRandom.class);
-		final Clock clock = context.mock(Clock.class);
-
-		final DuplexPlugin plugin = context.mock(DuplexPlugin.class);
-		final TransportId transportId = new TransportId("id");
 
 		context.checking(new Expectations() {{
 			allowing(plugin).getId();
@@ -270,6 +231,7 @@ public class PollerTest extends BrambleTestCase {
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
 					with((long) pollingInterval), with(MILLISECONDS));
+			will(returnValue(future));
 			// Second event
 			// Get the plugin
 			oneOf(pluginManager).getPlugin(transportId);
@@ -291,28 +253,60 @@ public class PollerTest extends BrambleTestCase {
 				false));
 		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
 				false));
-
-		context.assertIsSatisfied();
 	}
 
 	@Test
-	public void testPollOnTransportEnabled() throws Exception {
+	public void testRescheduleReplacesLaterTask() throws Exception {
-		Mockery context = new Mockery();
+		Plugin plugin = context.mock(Plugin.class);
-		context.setImposteriser(ClassImposteriser.INSTANCE);
-		final Executor ioExecutor = new ImmediateExecutor();
-		final ScheduledExecutorService scheduler =
-				context.mock(ScheduledExecutorService.class);
-		final ConnectionManager connectionManager =
-				context.mock(ConnectionManager.class);
-		final ConnectionRegistry connectionRegistry =
-				context.mock(ConnectionRegistry.class);
-		final PluginManager pluginManager = context.mock(PluginManager.class);
-		final SecureRandom random = context.mock(SecureRandom.class);
-		final Clock clock = context.mock(Clock.class);
 
-		final Plugin plugin = context.mock(Plugin.class);
+		context.checking(new Expectations() {{
-		final TransportId transportId = new TransportId("id");
+			allowing(plugin).getId();
-		final List<ContactId> connected = Collections.singletonList(contactId);
+			will(returnValue(transportId));
+			// First event
+			// Get the plugin
+			oneOf(pluginManager).getPlugin(transportId);
+			will(returnValue(plugin));
+			// The plugin supports polling
+			oneOf(plugin).shouldPoll();
+			will(returnValue(true));
+			// Schedule the next poll
+			oneOf(plugin).getPollingInterval();
+			will(returnValue(pollingInterval));
+			oneOf(clock).currentTimeMillis();
+			will(returnValue(now));
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
+					with((long) pollingInterval), with(MILLISECONDS));
+			will(returnValue(future));
+			// Second event
+			// Get the plugin
+			oneOf(pluginManager).getPlugin(transportId);
+			will(returnValue(plugin));
+			// The plugin supports polling
+			oneOf(plugin).shouldPoll();
+			will(returnValue(true));
+			// Replace the previously scheduled task, due later
+			oneOf(plugin).getPollingInterval();
+			will(returnValue(pollingInterval - 2));
+			oneOf(clock).currentTimeMillis();
+			will(returnValue(now + 1));
+			oneOf(future).cancel(false);
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
+					with((long) pollingInterval - 2), with(MILLISECONDS));
+		}});
+
+		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
+				connectionRegistry, pluginManager, random, clock);
+
+		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
+				false));
+		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
+				false));
+	}
+
+	@Test
+	public void testPollsOnTransportEnabled() throws Exception {
+		Plugin plugin = context.mock(Plugin.class);
+		List<ContactId> connected = Collections.singletonList(contactId);
 
 		context.checking(new Expectations() {{
 			allowing(plugin).getId();
@@ -328,6 +322,7 @@ public class PollerTest extends BrambleTestCase {
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)), with(0L),
 					with(MILLISECONDS));
+			will(returnValue(future));
 			will(new RunAction());
 			// Running the polling task schedules the next polling task
 			oneOf(plugin).getPollingInterval();
@@ -338,6 +333,7 @@ public class PollerTest extends BrambleTestCase {
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
 					with((long) (pollingInterval * 0.5)), with(MILLISECONDS));
+			will(returnValue(future));
 			// Poll the plugin
 			oneOf(connectionRegistry).getConnectedContacts(transportId);
 			will(returnValue(connected));
@@ -348,7 +344,36 @@ public class PollerTest extends BrambleTestCase {
 				connectionRegistry, pluginManager, random, clock);
 
 		p.eventOccurred(new TransportEnabledEvent(transportId));
+	}
 
-		context.assertIsSatisfied();
+	@Test
+	public void testCancelsPollingOnTransportDisabled() throws Exception {
+		Plugin plugin = context.mock(Plugin.class);
+		List<ContactId> connected = Collections.singletonList(contactId);
+
+		context.checking(new Expectations() {{
+			allowing(plugin).getId();
+			will(returnValue(transportId));
+			// Get the plugin
+			oneOf(pluginManager).getPlugin(transportId);
+			will(returnValue(plugin));
+			// The plugin supports polling
+			oneOf(plugin).shouldPoll();
+			will(returnValue(true));
+			// Schedule a polling task immediately
+			oneOf(clock).currentTimeMillis();
+			will(returnValue(now));
+			oneOf(scheduler).schedule(with(any(Runnable.class)), with(0L),
+					with(MILLISECONDS));
+			will(returnValue(future));
+			// The plugin is disabled before the task runs - cancel the task
+			oneOf(future).cancel(false);
+		}});
+
+		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
+				connectionRegistry, pluginManager, random, clock);
+
+		p.eventOccurred(new TransportEnabledEvent(transportId));
+		p.eventOccurred(new TransportDisabledEvent(transportId));
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/plugin/tcp/LanTcpPluginTest.java

@@ -11,6 +11,7 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.plugin.tcp.LanTcpPlugin.LanAddressComparator;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.junit.Test;
 
@@ -22,6 +23,7 @@ import java.net.NetworkInterface;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.Hashtable;
 import java.util.Map;
 import java.util.concurrent.Callable;
@@ -56,6 +58,9 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		// Local and remote in 192.168.0.0/16 should return true
 		assertTrue(plugin.addressesAreOnSameLan(makeAddress(192, 168, 0, 0),
 				makeAddress(192, 168, 255, 255)));
+		// Local and remote in 169.254.0.0/16 (link-local) should return true
+		assertTrue(plugin.addressesAreOnSameLan(makeAddress(169, 254, 0, 0),
+				makeAddress(169, 254, 255, 255)));
 		// Local and remote in different recognised prefixes should return false
 		assertFalse(plugin.addressesAreOnSameLan(makeAddress(10, 0, 0, 0),
 				makeAddress(172, 31, 255, 255)));
@@ -145,11 +150,11 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		assertEquals(2, split.length);
 		String addrString = split[0];
 		// Listen on the same interface as the plugin
-		final ServerSocket ss = new ServerSocket();
+		ServerSocket ss = new ServerSocket();
 		ss.bind(new InetSocketAddress(addrString, 0), 10);
 		int port = ss.getLocalPort();
-		final CountDownLatch latch = new CountDownLatch(1);
+		CountDownLatch latch = new CountDownLatch(1);
-		final AtomicBoolean error = new AtomicBoolean(false);
+		AtomicBoolean error = new AtomicBoolean(false);
 		new Thread() {
 			@Override
 			public void run() {
@@ -194,8 +199,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 				plugin.createKeyAgreementListener(new byte[COMMIT_LENGTH]);
 		assertNotNull(kal);
 		Callable<KeyAgreementConnection> c = kal.listen();
-		FutureTask<KeyAgreementConnection> f =
+		FutureTask<KeyAgreementConnection> f = new FutureTask<>(c);
-				new FutureTask<KeyAgreementConnection>(c);
 		new Thread(f).start();
 		// The plugin should have bound a socket and stored the port number
 		BdfList descriptor = kal.getDescriptor();
@@ -240,10 +244,10 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		assertEquals(2, split.length);
 		String addrString = split[0];
 		// Listen on the same interface as the plugin
-		final ServerSocket ss = new ServerSocket();
+		ServerSocket ss = new ServerSocket();
 		ss.bind(new InetSocketAddress(addrString, 0), 10);
-		final CountDownLatch latch = new CountDownLatch(1);
+		CountDownLatch latch = new CountDownLatch(1);
-		final AtomicBoolean error = new AtomicBoolean(false);
+		AtomicBoolean error = new AtomicBoolean(false);
 		new Thread() {
 			@Override
 			public void run() {
@@ -276,6 +280,57 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		plugin.stop();
 	}
 
+	@Test
+	public void testComparatorPrefersNonZeroPorts() throws Exception {
+		Comparator<InetSocketAddress> comparator = new LanAddressComparator();
+		InetSocketAddress nonZero = new InetSocketAddress("1.2.3.4", 1234);
+		InetSocketAddress zero = new InetSocketAddress("1.2.3.4", 0);
+
+		assertEquals(0, comparator.compare(nonZero, nonZero));
+		assertTrue(comparator.compare(nonZero, zero) < 0);
+
+		assertTrue(comparator.compare(zero, nonZero) > 0);
+		assertEquals(0, comparator.compare(zero, zero));
+	}
+
+	@Test
+	public void testComparatorPrefersLongerPrefixes() throws Exception {
+		Comparator<InetSocketAddress> comparator = new LanAddressComparator();
+		InetSocketAddress prefix192 = new InetSocketAddress("192.168.0.1", 0);
+		InetSocketAddress prefix172 = new InetSocketAddress("172.16.0.1", 0);
+		InetSocketAddress prefix10 = new InetSocketAddress("10.0.0.1", 0);
+
+		assertEquals(0, comparator.compare(prefix192, prefix192));
+		assertTrue(comparator.compare(prefix192, prefix172) < 0);
+		assertTrue(comparator.compare(prefix192, prefix10) < 0);
+
+		assertTrue(comparator.compare(prefix172, prefix192) > 0);
+		assertEquals(0, comparator.compare(prefix172, prefix172));
+		assertTrue(comparator.compare(prefix172, prefix10) < 0);
+
+		assertTrue(comparator.compare(prefix10, prefix192) > 0);
+		assertTrue(comparator.compare(prefix10, prefix172) > 0);
+		assertEquals(0, comparator.compare(prefix10, prefix10));
+	}
+
+	@Test
+	public void testComparatorPrefersSiteLocalToLinkLocal() throws Exception {
+		Comparator<InetSocketAddress> comparator = new LanAddressComparator();
+		InetSocketAddress prefix192 = new InetSocketAddress("192.168.0.1", 0);
+		InetSocketAddress prefix172 = new InetSocketAddress("172.16.0.1", 0);
+		InetSocketAddress prefix10 = new InetSocketAddress("10.0.0.1", 0);
+		InetSocketAddress linkLocal = new InetSocketAddress("169.254.0.1", 0);
+
+		assertTrue(comparator.compare(prefix192, linkLocal) < 0);
+		assertTrue(comparator.compare(prefix172, linkLocal) < 0);
+		assertTrue(comparator.compare(prefix10, linkLocal) < 0);
+
+		assertTrue(comparator.compare(linkLocal, prefix192) > 0);
+		assertTrue(comparator.compare(linkLocal, prefix172) > 0);
+		assertTrue(comparator.compare(linkLocal, prefix10) > 0);
+		assertEquals(0, comparator.compare(linkLocal, linkLocal));
+	}
+
 	private boolean systemHasLocalIpv4Address() throws Exception {
 		for (NetworkInterface i : Collections.list(
 				NetworkInterface.getNetworkInterfaces())) {
@@ -291,7 +346,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 	private static class Callback implements DuplexPluginCallback {
 
 		private final Map<ContactId, TransportProperties> remote =
-				new Hashtable<ContactId, TransportProperties>();
+				new Hashtable<>();
 		private final CountDownLatch propertiesLatch = new CountDownLatch(1);
 		private final CountDownLatch connectionsLatch = new CountDownLatch(1);
 		private final TransportProperties local = new TransportProperties();
@@ -311,6 +366,11 @@ public class LanTcpPluginTest extends BrambleTestCase {
 			return remote;
 		}
 
+		@Override
+		public TransportProperties getRemoteProperties(ContactId c) {
+			return remote.get(c);
+		}
+
 		@Override
 		public void mergeSettings(Settings s) {
 		}

bramble-core/src/test/java/org/briarproject/bramble/properties/TransportPropertyManagerImplTest.java

@@ -0,0 +1,723 @@
+package org.briarproject.bramble.properties;
+
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.client.ContactGroupFactory;
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfEntry;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataParser;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.jmock.Expectations;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
+import static org.briarproject.bramble.api.properties.TransportPropertyManager.CLIENT_ID;
+import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
+import static org.briarproject.bramble.test.TestUtils.getRandomId;
+import static org.briarproject.bramble.util.StringUtils.getRandomString;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+
+public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
+
+	private final DatabaseComponent db = context.mock(DatabaseComponent.class);
+	private final ClientHelper clientHelper = context.mock(ClientHelper.class);
+	private final MetadataParser metadataParser =
+			context.mock(MetadataParser.class);
+	private final ContactGroupFactory contactGroupFactory =
+			context.mock(ContactGroupFactory.class);
+	private final Clock clock = context.mock(Clock.class);
+
+	private final Group localGroup = getGroup();
+	private final LocalAuthor localAuthor = getLocalAuthor();
+	private final BdfDictionary fooPropertiesDict = BdfDictionary.of(
+			new BdfEntry("fooKey1", "fooValue1"),
+			new BdfEntry("fooKey2", "fooValue2")
+	);
+	private final BdfDictionary barPropertiesDict = BdfDictionary.of(
+			new BdfEntry("barKey1", "barValue1"),
+			new BdfEntry("barKey2", "barValue2")
+	);
+	private final TransportProperties fooProperties, barProperties;
+
+	private int nextContactId = 0;
+
+	public TransportPropertyManagerImplTest() throws Exception {
+		fooProperties = new TransportProperties();
+		for (String key : fooPropertiesDict.keySet())
+			fooProperties.put(key, fooPropertiesDict.getString(key));
+		barProperties = new TransportProperties();
+		for (String key : barPropertiesDict.keySet())
+			barProperties.put(key, barPropertiesDict.getString(key));
+	}
+
+	private TransportPropertyManagerImpl createInstance() {
+		context.checking(new Expectations() {{
+			oneOf(contactGroupFactory).createLocalGroup(CLIENT_ID);
+			will(returnValue(localGroup));
+		}});
+		return new TransportPropertyManagerImpl(db, clientHelper,
+				metadataParser, contactGroupFactory, clock);
+	}
+
+	@Test
+	public void testCreatesGroupsAtStartup() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact1 = getContact(true);
+		Contact contact2 = getContact(true);
+		List<Contact> contacts = Arrays.asList(contact1, contact2);
+		Group contactGroup1 = getGroup(), contactGroup2 = getGroup();
+
+		context.checking(new Expectations() {{
+			oneOf(db).containsGroup(txn, localGroup.getId());
+			will(returnValue(false));
+			oneOf(db).addGroup(txn, localGroup);
+			oneOf(db).getContacts(txn);
+			will(returnValue(contacts));
+			// The first contact's group has already been set up
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact1);
+			will(returnValue(contactGroup1));
+			oneOf(db).containsGroup(txn, contactGroup1.getId());
+			will(returnValue(true));
+			// The second contact's group hasn't been set up
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact2);
+			will(returnValue(contactGroup2));
+			oneOf(db).containsGroup(txn, contactGroup2.getId());
+			will(returnValue(false));
+			oneOf(db).addGroup(txn, contactGroup2);
+			oneOf(db).setGroupVisibility(txn, contact2.getId(),
+					contactGroup2.getId(), SHARED);
+		}});
+		// Copy the latest local properties into the group
+		expectGetLocalProperties(txn);
+		expectStoreMessage(txn, contactGroup2.getId(), "foo", fooPropertiesDict,
+				1, true, true);
+		expectStoreMessage(txn, contactGroup2.getId(), "bar", barPropertiesDict,
+				1, true, true);
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.createLocalState(txn);
+	}
+
+	@Test
+	public void testDoesNotCreateGroupsAtStartupIfAlreadyCreated()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+
+		context.checking(new Expectations() {{
+			oneOf(db).containsGroup(txn, localGroup.getId());
+			will(returnValue(true));
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.createLocalState(txn);
+	}
+
+	@Test
+	public void testCreatesContactGroupWhenAddingContact() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact(true);
+		Group contactGroup = getGroup();
+
+		context.checking(new Expectations() {{
+			// Create the group and share it with the contact
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).containsGroup(txn, contactGroup.getId());
+			will(returnValue(false));
+			oneOf(db).addGroup(txn, contactGroup);
+			oneOf(db).setGroupVisibility(txn, contact.getId(),
+					contactGroup.getId(), SHARED);
+		}});
+		// Copy the latest local properties into the group
+		expectGetLocalProperties(txn);
+		expectStoreMessage(txn, contactGroup.getId(), "foo", fooPropertiesDict,
+				1, true, true);
+		expectStoreMessage(txn, contactGroup.getId(), "bar", barPropertiesDict,
+				1, true, true);
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.addingContact(txn, contact);
+	}
+
+	@Test
+	public void testRemovesGroupWhenRemovingContact() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact(true);
+		Group contactGroup = getGroup();
+
+		context.checking(new Expectations() {{
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).removeGroup(txn, contactGroup);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.removingContact(txn, contact);
+	}
+
+	@Test
+	public void testDoesNotDeleteAnythingWhenFirstUpdateIsDelivered()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		GroupId contactGroupId = new GroupId(getRandomId());
+		long timestamp = 123456789;
+		Message message = getMessage(contactGroupId, timestamp);
+		Metadata meta = new Metadata();
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 2),
+				new BdfEntry("local", false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata =
+				new LinkedHashMap<>();
+		// A remote update for another transport should be ignored
+		MessageId barUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(barUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "bar"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", false)
+		));
+		// A local update for the same transport should be ignored
+		MessageId localUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(localUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", true)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(metadataParser).parse(meta);
+			will(returnValue(metaDictionary));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroupId);
+			will(returnValue(messageMetadata));
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		assertFalse(t.incomingMessage(txn, message, meta));
+	}
+
+	@Test
+	public void testDeletesOlderUpdatesWhenUpdateIsDelivered()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		GroupId contactGroupId = new GroupId(getRandomId());
+		long timestamp = 123456789;
+		Message message = getMessage(contactGroupId, timestamp);
+		Metadata meta = new Metadata();
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 4),
+				new BdfEntry("local", false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata =
+				new LinkedHashMap<>();
+		// Old remote updates for the same transport should be deleted
+		MessageId fooVersion2 = new MessageId(getRandomId());
+		messageMetadata.put(fooVersion2, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 2),
+				new BdfEntry("local", false)
+		));
+		MessageId fooVersion1 = new MessageId(getRandomId());
+		messageMetadata.put(fooVersion1, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", false)
+		));
+		MessageId fooVersion3 = new MessageId(getRandomId());
+		messageMetadata.put(fooVersion3, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 3),
+				new BdfEntry("local", false)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(metadataParser).parse(meta);
+			will(returnValue(metaDictionary));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroupId);
+			will(returnValue(messageMetadata));
+			// Versions 1-3 should be deleted
+			oneOf(db).deleteMessage(txn, fooVersion1);
+			oneOf(db).deleteMessageMetadata(txn, fooVersion1);
+			oneOf(db).deleteMessage(txn, fooVersion2);
+			oneOf(db).deleteMessageMetadata(txn, fooVersion2);
+			oneOf(db).deleteMessage(txn, fooVersion3);
+			oneOf(db).deleteMessageMetadata(txn, fooVersion3);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		assertFalse(t.incomingMessage(txn, message, meta));
+	}
+
+	@Test
+	public void testDeletesObsoleteUpdateWhenDelivered() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		GroupId contactGroupId = new GroupId(getRandomId());
+		long timestamp = 123456789;
+		Message message = getMessage(contactGroupId, timestamp);
+		Metadata meta = new Metadata();
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 3),
+				new BdfEntry("local", false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata =
+				new LinkedHashMap<>();
+		// Old remote updates for the same transport should be deleted
+		MessageId fooVersion2 = new MessageId(getRandomId());
+		messageMetadata.put(fooVersion2, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 2),
+				new BdfEntry("local", false)
+		));
+		MessageId fooVersion1 = new MessageId(getRandomId());
+		messageMetadata.put(fooVersion1, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", false)
+		));
+		// A newer remote update for the same transport should not be deleted
+		MessageId fooVersion4 = new MessageId(getRandomId());
+		messageMetadata.put(fooVersion4, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 4),
+				new BdfEntry("local", false)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(metadataParser).parse(meta);
+			will(returnValue(metaDictionary));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroupId);
+			will(returnValue(messageMetadata));
+			// Versions 1 and 2 should be deleted, version 4 should not
+			oneOf(db).deleteMessage(txn, fooVersion1);
+			oneOf(db).deleteMessageMetadata(txn, fooVersion1);
+			oneOf(db).deleteMessage(txn, fooVersion2);
+			oneOf(db).deleteMessageMetadata(txn, fooVersion2);
+			// The update being delivered (version 3) should be deleted
+			oneOf(db).deleteMessage(txn, message.getId());
+			oneOf(db).deleteMessageMetadata(txn, message.getId());
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		assertFalse(t.incomingMessage(txn, message, meta));
+	}
+
+	@Test
+	public void testStoresRemotePropertiesWithVersion0() throws Exception {
+		Contact contact = getContact(true);
+		Group contactGroup = getGroup();
+		Transaction txn = new Transaction(null, false);
+		Map<TransportId, TransportProperties> properties =
+				new LinkedHashMap<>();
+		properties.put(new TransportId("foo"), fooProperties);
+		properties.put(new TransportId("bar"), barProperties);
+
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact);
+			will(returnValue(contactGroup));
+		}});
+		expectStoreMessage(txn, contactGroup.getId(), "foo", fooPropertiesDict,
+				0, false, false);
+		expectStoreMessage(txn, contactGroup.getId(), "bar", barPropertiesDict,
+				0, false, false);
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.addRemoteProperties(txn, contact.getId(), properties);
+	}
+
+	@Test
+	public void testReturnsLatestLocalProperties() throws Exception {
+		Transaction txn = new Transaction(null, false);
+
+		expectGetLocalProperties(txn);
+
+		TransportPropertyManagerImpl t = createInstance();
+		Map<TransportId, TransportProperties> local = t.getLocalProperties(txn);
+		assertEquals(2, local.size());
+		assertEquals(fooProperties, local.get(new TransportId("foo")));
+		assertEquals(barProperties, local.get(new TransportId("bar")));
+	}
+
+	@Test
+	public void testReturnsEmptyPropertiesIfNoLocalPropertiesAreFound()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Map<MessageId, BdfDictionary> messageMetadata =
+				new LinkedHashMap<>();
+		// A local update for another transport should be ignored
+		MessageId barUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(barUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "bar"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", true)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		assertEquals(0, t.getLocalProperties(new TransportId("foo")).size());
+	}
+
+	@Test
+	public void testReturnsLocalProperties() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Map<MessageId, BdfDictionary> messageMetadata =
+				new LinkedHashMap<>();
+		// A local update for another transport should be ignored
+		MessageId barUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(barUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "bar"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", true)
+		));
+		// A local update for the right transport should be returned
+		MessageId fooUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(fooUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", true)
+		));
+		BdfList fooUpdate = BdfList.of("foo", 1, fooPropertiesDict);
+
+		context.checking(new Expectations() {{
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, fooUpdateId);
+			will(returnValue(fooUpdate));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		assertEquals(fooProperties,
+				t.getLocalProperties(new TransportId("foo")));
+	}
+
+	@Test
+	public void testReturnsRemotePropertiesOrEmptyProperties()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact1 = getContact(false);
+		Contact contact2 = getContact(true);
+		Contact contact3 = getContact(true);
+		List<Contact> contacts =
+				Arrays.asList(contact1, contact2, contact3);
+		Group contactGroup2 = getGroup();
+		Group contactGroup3 = getGroup();
+		Map<MessageId, BdfDictionary> messageMetadata3 =
+				new LinkedHashMap<>();
+		// A remote update for another transport should be ignored
+		MessageId barUpdateId = new MessageId(getRandomId());
+		messageMetadata3.put(barUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "bar"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", false)
+		));
+		// A local update for the right transport should be ignored
+		MessageId localUpdateId = new MessageId(getRandomId());
+		messageMetadata3.put(localUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", true)
+		));
+		// A remote update for the right transport should be returned
+		MessageId fooUpdateId = new MessageId(getRandomId());
+		messageMetadata3.put(fooUpdateId, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", false)
+		));
+		BdfList fooUpdate = BdfList.of("foo", 1, fooPropertiesDict);
+
+		context.checking(new Expectations() {{
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
+			oneOf(db).getContacts(txn);
+			will(returnValue(contacts));
+			// First contact: skipped because not active
+			// Second contact: no updates
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact2);
+			will(returnValue(contactGroup2));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup2.getId());
+			will(returnValue(Collections.emptyMap()));
+			// Third contact: returns an update
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact3);
+			will(returnValue(contactGroup3));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup3.getId());
+			will(returnValue(messageMetadata3));
+			oneOf(clientHelper).getMessageAsList(txn, fooUpdateId);
+			will(returnValue(fooUpdate));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		Map<ContactId, TransportProperties> properties =
+				t.getRemoteProperties(new TransportId("foo"));
+		assertEquals(3, properties.size());
+		assertEquals(0, properties.get(contact1.getId()).size());
+		assertEquals(0, properties.get(contact2.getId()).size());
+		assertEquals(fooProperties, properties.get(contact3.getId()));
+	}
+
+	@Test
+	public void testMergingUnchangedPropertiesDoesNotCreateUpdate()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		MessageId updateId = new MessageId(getRandomId());
+		Map<MessageId, BdfDictionary> messageMetadata =
+				Collections.singletonMap(updateId, BdfDictionary.of(
+						new BdfEntry("transportId", "foo"),
+						new BdfEntry("version", 1),
+						new BdfEntry("local", true)
+				));
+		BdfList update = BdfList.of("foo", 1, fooPropertiesDict);
+
+		context.checking(new Expectations() {{
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
+			// Merge the new properties with the existing properties
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, updateId);
+			will(returnValue(update));
+			// Properties are unchanged so we're done
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.mergeLocalProperties(new TransportId("foo"), fooProperties);
+	}
+
+	@Test
+	public void testMergingNewPropertiesCreatesUpdate() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact(true);
+		Group contactGroup = getGroup();
+
+		context.checking(new Expectations() {{
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
+			// There are no existing properties to merge with
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(Collections.emptyMap()));
+			// Store the new properties in the local group, version 1
+			expectStoreMessage(txn, localGroup.getId(), "foo",
+					fooPropertiesDict, 1, true, false);
+			// Store the new properties in each contact's group, version 1
+			oneOf(db).getContacts(txn);
+			will(returnValue(Collections.singletonList(contact)));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(Collections.emptyMap()));
+			expectStoreMessage(txn, contactGroup.getId(), "foo",
+					fooPropertiesDict, 1, true, true);
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.mergeLocalProperties(new TransportId("foo"), fooProperties);
+	}
+
+	@Test
+	public void testMergingUpdatedPropertiesCreatesUpdate() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact(true);
+		Group contactGroup = getGroup();
+		BdfDictionary oldMetadata = BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 1),
+				new BdfEntry("local", true)
+		);
+		MessageId localGroupUpdateId = new MessageId(getRandomId());
+		Map<MessageId, BdfDictionary> localGroupMessageMetadata =
+				Collections.singletonMap(localGroupUpdateId, oldMetadata);
+		MessageId contactGroupUpdateId = new MessageId(getRandomId());
+		Map<MessageId, BdfDictionary> contactGroupMessageMetadata =
+				Collections.singletonMap(contactGroupUpdateId, oldMetadata);
+		BdfList oldUpdate = BdfList.of("foo", 1, BdfDictionary.of(
+				new BdfEntry("fooKey1", "oldFooValue1")
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
+			// Merge the new properties with the existing properties
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(localGroupMessageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, localGroupUpdateId);
+			will(returnValue(oldUpdate));
+			// Store the merged properties in the local group, version 2
+			expectStoreMessage(txn, localGroup.getId(), "foo",
+					fooPropertiesDict, 2, true, false);
+			// Delete the previous update
+			oneOf(db).removeMessage(txn, localGroupUpdateId);
+			// Store the merged properties in each contact's group, version 2
+			oneOf(db).getContacts(txn);
+			will(returnValue(Collections.singletonList(contact)));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(contactGroupMessageMetadata));
+			expectStoreMessage(txn, contactGroup.getId(), "foo",
+					fooPropertiesDict, 2, true, true);
+			// Delete the previous update
+			oneOf(db).removeMessage(txn, contactGroupUpdateId);
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.mergeLocalProperties(new TransportId("foo"), fooProperties);
+	}
+
+	private Group getGroup() {
+		GroupId g = new GroupId(getRandomId());
+		byte[] descriptor = getRandomBytes(MAX_GROUP_DESCRIPTOR_LENGTH);
+		return new Group(g, CLIENT_ID, descriptor);
+	}
+
+	private LocalAuthor getLocalAuthor() {
+		AuthorId id = new AuthorId(getRandomId());
+		String name = getRandomString(MAX_AUTHOR_NAME_LENGTH);
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		long created = System.currentTimeMillis();
+		return new LocalAuthor(id, name, publicKey, privateKey, created);
+	}
+
+	private Contact getContact(boolean active) {
+		ContactId c = new ContactId(nextContactId++);
+		AuthorId a = new AuthorId(getRandomId());
+		String name = getRandomString(MAX_AUTHOR_NAME_LENGTH);
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		return new Contact(c, new Author(a, name, publicKey),
+				localAuthor.getId(), true, active);
+	}
+
+	private Message getMessage(GroupId g, long timestamp) {
+		MessageId messageId = new MessageId(getRandomId());
+		byte[] raw = getRandomBytes(MAX_MESSAGE_BODY_LENGTH);
+		return new Message(messageId, g, timestamp, raw);
+	}
+
+	private void expectGetLocalProperties(Transaction txn)
+			throws Exception {
+		Map<MessageId, BdfDictionary> messageMetadata =
+				new LinkedHashMap<>();
+		// The only update for transport "foo" should be returned
+		MessageId fooVersion999 = new MessageId(getRandomId());
+		messageMetadata.put(fooVersion999, BdfDictionary.of(
+				new BdfEntry("transportId", "foo"),
+				new BdfEntry("version", 999)
+		));
+		// An old update for transport "bar" should be deleted
+		MessageId barVersion2 = new MessageId(getRandomId());
+		messageMetadata.put(barVersion2, BdfDictionary.of(
+				new BdfEntry("transportId", "bar"),
+				new BdfEntry("version", 2)
+		));
+		// An even older update for transport "bar" should be deleted
+		MessageId barVersion1 = new MessageId(getRandomId());
+		messageMetadata.put(barVersion1, BdfDictionary.of(
+				new BdfEntry("transportId", "bar"),
+				new BdfEntry("version", 1)
+		));
+		// The latest update for transport "bar" should be returned
+		MessageId barVersion3 = new MessageId(getRandomId());
+		messageMetadata.put(barVersion3, BdfDictionary.of(
+				new BdfEntry("transportId", "bar"),
+				new BdfEntry("version", 3)
+		));
+		BdfList fooUpdate = BdfList.of("foo", 999, fooPropertiesDict);
+		BdfList barUpdate = BdfList.of("bar", 3, barPropertiesDict);
+
+		context.checking(new Expectations() {{
+			// Find the latest local update for each transport
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(db).removeMessage(txn, barVersion1);
+			oneOf(db).removeMessage(txn, barVersion2);
+			// Retrieve and parse the latest local properties
+			oneOf(clientHelper).getMessageAsList(txn, fooVersion999);
+			will(returnValue(fooUpdate));
+			oneOf(clientHelper).getMessageAsList(txn, barVersion3);
+			will(returnValue(barUpdate));
+		}});
+	}
+
+	private void expectStoreMessage(Transaction txn, GroupId g,
+			String transportId, BdfDictionary properties, long version,
+			boolean local, boolean shared) throws Exception {
+		long timestamp = 123456789;
+		BdfList body = BdfList.of(transportId, version, properties);
+		Message message = getMessage(g, timestamp);
+		BdfDictionary meta = BdfDictionary.of(
+				new BdfEntry("transportId", transportId),
+				new BdfEntry("version", version),
+				new BdfEntry("local", local)
+		);
+
+		context.checking(new Expectations() {{
+			oneOf(clock).currentTimeMillis();
+			will(returnValue(timestamp));
+			oneOf(clientHelper).createMessage(g, timestamp, body);
+			will(returnValue(message));
+			oneOf(clientHelper).addLocalMessage(txn, message, meta, shared);
+		}});
+	}
+}