I've been debugging and reading a lot this weekend to find an explanation. And I'm not 100% sure, but I think I found one. When executing an asynchronous method invocation, the jboss backend server will create a callback object allowing to process the final result of the asynchronous invocation. If you don't process those callbacks, they remain on the server. I think this is similar like the FutureResult object to follow up asynchronous method invocations. More info can be found here: http://www.onjava.com/pub/a/onjava/2005/02/23/remoting.html View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4180442#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...