Has JBoss' stance here changed? I've got a similar problem. I have a remote SLSB that takes Object instances and stores them in a cache - that's the plan anyway. Unfortunately, whenever I pass in any object implementation I receive the same error. Seems to me that this is not expected behavior since it is reasonable to suspect that if a method accepts some object Foo, then it should accept any FooImplementingOrExtending object. I think that's one of the tenants of OOP, no? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4177531#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...