If I remember correctly... Entity Beans could be marked as "reentrant". Session Beans did not require a "reentrant" marking because if Stateless, the container would return another separate instance, and Stateful was prohibited (as it is now)... EJB 2.1 Spec, Final Draft, 7.12.10: anonymous wrote : The container must ensure that only one thread can be executing an instance at any time. If a client | request arrives for an instance while the instance is executing another request, the container may throw | the java.rmi.RemoteException to the second request if the client is a remote client, or the | javax.ejb.EJBException if the client is a local client.[9] | | Note that a session object is intended to support only a single client. Therefore, it would be an | application error if two clients attempted to invoke the same session object. | | One implication of this rule is that an application cannot make loopback calls to a session bean instance. S, ALR View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3989541#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...