Some further experiments showed that the same problem also exists with a single server running on Linux (and one Windows client). Hence, it is not related to Solaris and not to running multiple instances in parallel. It is not our application code that tries to recover from the client-side JMSException (and thus leading to the server-side mismatch exception). It has to be caused by the Messaging and/or Remoting internals. Thanks for any suggestions. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3999917#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...