Use Animal Sniffer to check Java 6 API compatibility.

.gitlab-ci.yml

@@ -10,17 +10,10 @@ before_script:
   - export GRADLE_USER_HOME=$PWD/.gradle
   # Accept the license for the Android build tools
   - echo y | /opt/android-sdk/tools/bin/sdkmanager "build-tools;26.0.2"
-  # Download OpenJDK 6 so we can compile against its standard library
-  - JDK_FILE=openjdk-6-jre-headless_6b38-1.13.10-1~deb7u1_amd64.deb
-  - if [ ! -d openjdk ]
-  - then
-  - wget -q http://ftp.uk.debian.org/debian/pool/main/o/openjdk-6/$JDK_FILE
-  - dpkg-deb -x $JDK_FILE openjdk
-  - fi
-  - export JAVA_6_HOME=$PWD/openjdk/usr/lib/jvm/java-6-openjdk-amd64
 
 test:
   script:
+    - ./gradlew animalSnifferMain animalSnifferTest
     - ./gradlew test
 
 after_script:

bramble-api/build.gradle

@@ -2,6 +2,7 @@ apply plugin: 'java-library'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
+apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'witness'
 
 dependencies {
@@ -14,6 +15,8 @@ dependencies {
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
 	testImplementation "org.hamcrest:hamcrest-library:1.3"
 	testImplementation "org.hamcrest:hamcrest-core:1.3"
+
+	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }
 
 dependencyVerification {
@@ -48,8 +51,3 @@ 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/build.gradle

@@ -2,6 +2,7 @@ apply plugin: 'java-library'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
+apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'net.ltgt.apt'
 apply plugin: 'idea'
 apply plugin: 'witness'
@@ -26,6 +27,8 @@ dependencies {
 	testImplementation "org.hamcrest:hamcrest-core:1.3"
 
 	testApt 'com.google.dagger:dagger-compiler:2.0.2'
+
+	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }
 
 dependencyVerification {
@@ -68,8 +71,3 @@ 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)
-}

briar-api/build.gradle

@@ -2,18 +2,16 @@ apply plugin: 'java-library'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
+apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'witness'
 
 dependencies {
 	implementation project(path: ':bramble-api', configuration: 'default')
+
+	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }
 
 dependencyVerification {
 	verify = [
 	]
 }
-
-// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
-tasks.withType(JavaCompile) {
-	useJava6StandardLibrary(it)
-}

briar-core/build.gradle

@@ -2,6 +2,7 @@ apply plugin: 'java-library'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
+apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'net.ltgt.apt'
 apply plugin: 'idea'
 apply plugin: 'witness'
@@ -27,6 +28,8 @@ dependencies {
 	testImplementation "org.hamcrest:hamcrest-core:1.3"
 
 	testApt 'com.google.dagger:dagger-compiler:2.0.2'
+
+	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }
 
 dependencyVerification {
@@ -59,8 +62,3 @@ dependencyVerification {
 			'org.slf4j:slf4j-api:1.7.16:slf4j-api-1.7.16.jar:e56288031f5e60652c06e7bb6e9fa410a61231ab54890f7b708fc6adc4107c5b',
 	]
 }
-
-// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
-tasks.withType(JavaCompile) {
-	useJava6StandardLibrary(it)
-}

build.gradle

@@ -22,30 +22,7 @@ buildscript {
 		classpath 'com.android.tools.build:gradle:3.1.2'
 		classpath 'net.ltgt.gradle:gradle-apt-plugin:0.9'
 		classpath 'de.undercouch:gradle-download-task:3.2.0'
+		classpath 'ru.vyarus:gradle-animalsniffer-plugin:1.4.3'
 		classpath files('libs/gradle-witness.jar')
 	}
 }
-
-// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
-ext.useJava6StandardLibrary = { task ->
-	def home = System.env.JAVA_6_HOME;
-	if (home != null && !home.isEmpty()) {
-		println "Setting Java 6 bootstrap classpath for ${task.name}"
-		task.dependsOn createJavaLangInvokeJar
-		task.options.bootstrapClasspath = files(
-				"${project.rootDir}/build/invoke.jar",
-				"${home}/jre/lib/rt.jar",
-				"${home}/jre/lib/jsse.jar"
-		)
-	}
-}
-
-// Create a jar containing the java.lang.invoke classes for the Java 6 bootstrap classpath
-task createJavaLangInvokeJar(type: Zip) {
-	archiveName 'invoke.jar'
-	destinationDir file("${project.rootDir}/build")
-	from zipTree("${System.getProperty('java.home')}/lib/rt.jar").matching {
-		include 'java/lang/invoke/*'
-	}
-	include '**/*'
-}