This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Inheritance in EJBs is not straightforward ... the main thing to keep in mind is that your bean implementation class can inherit from a base class ... however, your home and remote interfaces generally cannot. Typically, I use inheritance in EJBs only to provide some default implemenation of methods (such as the setEntityContext()), ejbActivate(), ejbPassivate(), etc. In this sense, this pattern is more of an adapter.