Might be quite fiddly. You could create your own classloader that loads it classes from a different place to the classpath used to run the servicecontainer. Allow it only access to the class used to set the object message. Then set the context classloader before running the test and verify the test passes (the test should try sending an object message with the body being the class that is only accessible by the special classloader) Unset the classloader and the test should fail. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4028821#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...