Thanks for the responses everyone. I think I have found a solution. I added debug code to testcase RequestReplyQueue and noticed that the test was receiving the following message text on the queue: High Priority Persistent message. This message text is placed on the queue by the previous testcase (QueueMessageOrder). The messages from the previous testcase were still on the queue, which appears to have lead to problems with the testcase RequestReplyQueue. Testcase RequestReplyQueue calls the method drainQueue to remove any leftover messages. However, from the test.log file I could tell that drainQueue was not removing any messages in the failing scenario. The code in drainQueue has a timeout of 50 milliseconds to receive a message. I guessed that maybe this was too short sometimes, so I increased the timeout from 50 to 500. After making this change, I have run the test 10 times in a row without a failure, so this appears to be the solution. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4222343#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...