There is something I don't understand here, please forgive my intrusion: Tomaz says that he uses MDBs. The RuntimeException is thrown from within MDB's onMessage(). 4.5.2 is about MessageListener's onMessage(), and actually the session's acknowledgment mode has bearing on the behavior. This is a different situation. Tomaz, what EJB version are you using? 2.1 or 3? Joining Tim in his request, could you please sent a test case that fails, or somehow guide us into replicating the failure? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982263#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...