Hello, I have two message driven beans and both of them persist entity through entity manager. Both message driven beans work in scope of one shared jta transaction. In this special case is it possible to call EntityManager.persist in those mdbs concurrently or shall I have to synchronize access to entity manager? Thanks for answer Best regards Pavel Kadlec View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4124820#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...