The Checker framework is an easily expansible set of check/transformation to build hierarchy of chain operations easily to-store/to-be created and re utilized (at run time if you want).
A Java EE 6 Reference Application likes Java Pet Store
A reference implementation of a Virutal Store that explores the key features of Java EE 6 API, including JSF 2.0 (with Primafaces components suite), JPA 2.0, EJB 3.1, Webservices, Validation through a complete working example.
For beginners and intermediate students of Java technology