A session bean class MUST NOT have a superclass that is itself a session bean class.
However EJB3 in action simply states that if you inherit another session bean, the @Stateful, @Stateless annotations are ignored. Rest of the callback methods, interceptor methods are inherited by the subclass bean.
What is true ? Is it allowed to inherit a session bean by another session bean ? Does 'MUST NOT' mean that in general it should be avoided ?