Alex, Can you be more specific? I read your note as saying you changed the method signature to protected synchronized Collection acquireJobs() but that shouldn't help, because it will synchronize on the thread object. But this won't prevent other threads from hitting it at the same time. Unless acquireJobs() is being called from a subclass of JobExecutorThread, the only place it is called from is run(), so there's not even a remote possibility of a cross-thread invocation somehow. If I understood you correctly, and this made the problem go away, I suspect it's just hiding for a while... -Ed Staub View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4049381#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...