That is not a valid mbean name. Do you mean, perhaps, the jboss.system:service=ThreadPool mbean? If that queue size is always zero, then you have enough threads to handle the incoming requests. By the way, blindly adding more threads to the pool does not guarantee better performance. Adding more load (threads, in this case) to an overloaded system (too many threads contending for system resources) is a classic performance anti-pattern. I think in your other post (which I can't find right now - now you know why you shouldn't post the same question in multiple locations, it makes it difficult to have a single coherent conversation) I also asked if you had looked at garbage collection performance. Have you done that? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4216989#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...