Sun's Bluperint reference implementation of Pet store is built on the JPA Controller pattern. I find no official EJB blueprints whatsoever.
When should you choose an EJB session bean vs a simple JPA controller? Should / could you use both?
Also, are there any server side validation patterns for both options? I know Java EE 6 has something in this regard, but I'm interested in Java EE 5 patterns for various reasons.