"bstansberry(a)jboss.cm" wrote : Saying it implements Serializable is insufficient; all of its fields must also implement Serializable or be declared transient. Somewhere in the DmWebSession's object graph there is a non-transient reference to the session itself (aka org.apache.catalina.session.StandardSessionFacade). StandardSessionFacade isn't serializable, so that won't work. And here that ref is: | public class DmWebSession extends UserSession { | | private HttpSession session_; HttpSession is an interface; the actual class of the object is StandardSessionFacade. You can't hold a ref to the session in a session attribute. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4038911#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...