diff --git a/briar-api/src/org/briarproject/api/clients/ProtocolStateException.java b/briar-api/src/org/briarproject/api/clients/ProtocolStateException.java
new file mode 100644
index 000000000..f7b072abf
--- /dev/null
+++ b/briar-api/src/org/briarproject/api/clients/ProtocolStateException.java
@@ -0,0 +1,11 @@
+package org.briarproject.api.clients;
+
+import org.briarproject.api.db.DbException;
+
+/**
+ * Thrown when a database operation is attempted as part of a protocol session
+ * and the operation is not applicable to the current protocol state.
+ */
+public class ProtocolStateException extends DbException {
+
+}
diff --git a/briar-api/src/org/briarproject/api/db/ContactExistsException.java b/briar-api/src/org/briarproject/api/db/ContactExistsException.java
index 6b4c283f5..8e27d9cc8 100644
--- a/briar-api/src/org/briarproject/api/db/ContactExistsException.java
+++ b/briar-api/src/org/briarproject/api/db/ContactExistsException.java
@@ -6,5 +6,4 @@ package org.briarproject.api.db;
  */
 public class ContactExistsException extends DbException {
 
-	private static final long serialVersionUID = -6658762011691502411L;
 }
diff --git a/briar-api/src/org/briarproject/api/db/DbClosedException.java b/briar-api/src/org/briarproject/api/db/DbClosedException.java
index decccf5e7..c8fbf6823 100644
--- a/briar-api/src/org/briarproject/api/db/DbClosedException.java
+++ b/briar-api/src/org/briarproject/api/db/DbClosedException.java
@@ -1,7 +1,8 @@
 package org.briarproject.api.db;
 
-/** Thrown when a database operation is attempted and the database is closed. */
+/**
+ * Thrown when a database operation is attempted and the database is closed.
+ */
 public class DbClosedException extends DbException {
 
-	private static final long serialVersionUID = -3679248177625310653L;
 }
diff --git a/briar-api/src/org/briarproject/api/db/DbException.java b/briar-api/src/org/briarproject/api/db/DbException.java
index d214d45e5..f111f9517 100644
--- a/briar-api/src/org/briarproject/api/db/DbException.java
+++ b/briar-api/src/org/briarproject/api/db/DbException.java
@@ -2,9 +2,8 @@ package org.briarproject.api.db;
 
 public class DbException extends Exception {
 
-	private static final long serialVersionUID = 3706581789209939441L;
-
-	public DbException() {}
+	public DbException() {
+	}
 
 	public DbException(Throwable t) {
 		super(t);
diff --git a/briar-api/src/org/briarproject/api/db/NoSuchContactException.java b/briar-api/src/org/briarproject/api/db/NoSuchContactException.java
index 6743521b4..9c2f5400b 100644
--- a/briar-api/src/org/briarproject/api/db/NoSuchContactException.java
+++ b/briar-api/src/org/briarproject/api/db/NoSuchContactException.java
@@ -7,5 +7,4 @@ package org.briarproject.api.db;
  */
 public class NoSuchContactException extends DbException {
 
-	private static final long serialVersionUID = -7048538231308207386L;
 }
diff --git a/briar-api/src/org/briarproject/api/db/NoSuchGroupException.java b/briar-api/src/org/briarproject/api/db/NoSuchGroupException.java
index 17e67f564..89222f58c 100644
--- a/briar-api/src/org/briarproject/api/db/NoSuchGroupException.java
+++ b/briar-api/src/org/briarproject/api/db/NoSuchGroupException.java
@@ -7,5 +7,4 @@ package org.briarproject.api.db;
  */
 public class NoSuchGroupException extends DbException {
 
-	private static final long serialVersionUID = -5494178507342571697L;
 }
diff --git a/briar-api/src/org/briarproject/api/db/NoSuchLocalAuthorException.java b/briar-api/src/org/briarproject/api/db/NoSuchLocalAuthorException.java
index 239e03cda..91f4aabe9 100644
--- a/briar-api/src/org/briarproject/api/db/NoSuchLocalAuthorException.java
+++ b/briar-api/src/org/briarproject/api/db/NoSuchLocalAuthorException.java
@@ -7,5 +7,4 @@ package org.briarproject.api.db;
  */
 public class NoSuchLocalAuthorException extends DbException {
 
-	private static final long serialVersionUID = 494398665376703860L;
 }
diff --git a/briar-api/src/org/briarproject/api/db/NoSuchMessageException.java b/briar-api/src/org/briarproject/api/db/NoSuchMessageException.java
index a28dbe02b..d7a5909e9 100644
--- a/briar-api/src/org/briarproject/api/db/NoSuchMessageException.java
+++ b/briar-api/src/org/briarproject/api/db/NoSuchMessageException.java
@@ -7,5 +7,4 @@ package org.briarproject.api.db;
  */
 public class NoSuchMessageException extends DbException {
 
-	private static final long serialVersionUID = 9191508339698803848L;
 }
diff --git a/briar-api/src/org/briarproject/api/db/NoSuchTransportException.java b/briar-api/src/org/briarproject/api/db/NoSuchTransportException.java
index 4c9c6ca12..d68a2cc30 100644
--- a/briar-api/src/org/briarproject/api/db/NoSuchTransportException.java
+++ b/briar-api/src/org/briarproject/api/db/NoSuchTransportException.java
@@ -7,5 +7,4 @@ package org.briarproject.api.db;
  */
 public class NoSuchTransportException extends DbException {
 
-	private static final long serialVersionUID = -6274982612759573100L;
 }