One observation about using a corePoolSize of 0. The most obvious reason you'd do this is to prevent a thread pool from having threads hanging around when there are no tasks. However, if you have a non-zero-length queue, then no threads will be started until the queue is full. This means that if the queue is never filled, the tasks will never run. I think that for this use case, the proper solution, introduced as of JDK6 into ThreadPoolExecutor, is to use a non-zero corePoolSize and enable core thread timeouts. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4196995#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...