Ok, I've created JBREM-1045 "ServerInvokerCallbackHandler can suffer deadlock when used with BlockingCallbackStore" (http://jira.jboss.org/jira/browse/JBREM-1045), applied a fix to branches 2.2 and 2.x, and attached a preview version of jboss-remoting.jar from the 2.2 branch. The fix is to change ServerInvokerCallbackHandler.handleCallback() by taking the call to persistCallback(), which ultimately calls BlockingCallbackStore.add(), out of the synchronized(callbacks) block. Jeremy, if you get a chance, let me know if the fix works for you. And thanks for pointing out the problem. -Ron View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4184615#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...