Current we support:
Hibernate 3.1
Java Persistence API (sometimes called JPA or EJB3 persistence)
Db4Objects (a lightweight object database)
It works inside a Java EE container, inside a plain Servlet environment or in a purely SE environment such as a desktop application (with obvious limitations--cant use session-per-http-request strategy outside a servlet environment for instance
Probst, Martin. “Processing Arbitrarily Large XML using a Persistent DOM.” Presented at Balisage: The Markup Conference 2010, Montréal, Canada, August 3 - 6, 2010. In Proceedings of Balisage: The Markup Conference 2010. Balisage Series on Markup Technologies, vol. 5 (2010). doi:10.4242/BalisageVol5.Probst01.