No, he wants to create a new group and uses another group as a template. That's how I understood it (I hope there's no misunderstanding ;)). sjmenden, are you sure you read the thread I posted above? It's very important to understand the 4 states entities can have. If you want to create a new group with a new id, then you really need Group newGroup = new Group();. When you want to merge an existing managed or detached entity (which you retrieved e.g. via em.find), it always keeps its id. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3967444#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...