Hi All I have a scenario and am trying to evaluate the performance of using the entity manager in a Message Driven Bean (MDB) class MDBean { @persistencecontext(....) private EntityManager em; public void onMessage() { .... while (someCondition) { ClassB b = new ClassB(); b.setEntityManager(em); b.doSomething(); } ............ } Basically ClassB carries out persisting of about 6 tables based on the entitymanager passed to it. This process happens in a loop and the loop runs for about 10 - 20 times. I was wondering if I need to close the entity maanger at some point and re-create it? What would be the performance hit if any? Let me know what other design considerations need to be taken into account? Thanks K View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3991534#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...