If you use UseIncomingPacketHandler, then you have *one* thread handling incoming messages. Otherwise, the multicast receiver thread and the unicast receiver thread will handle a message each. So there are effectively *no* thread pools in versions before 2.5. Note that 2.5 is API backwards compatible with all 2.2.9.x, so you could simply replace it. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4046322#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...