After some debugging I realized that I needed to increase MaximumPoolSize of WorkManagerThreadPool in jbossjca-service.xml ... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4171276#4171276 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4171276