Hibernate is a powerful, high performance object/relational persistence and query service. Hibernate lets you develop persistent classes following object-oriented idiom - including association, inheritance, polymorphism, composition, and collections. Hibernate allows you to express queries in its own portable SQL extension (HQL), as well as in native SQL, or with an object-oriented Criteria and Example API.
Hibernate 3.1.3 has been released with new features and promises on March 20, 2006. This is mainly a bug-fix release.
Changes in version 3.1.3 (2006.03.20)
* [HHH-535] - properties element causes exception in interface/abstract class
* [HHH-1236] - Remove static reference to classloader, to avoid memory leak at webapp reload
* [HHH-1248] - explicit joins to collections in subquery result in join conditions being dropped from sql
* [HHH-1287] - Problem with WAS ExtendedJTATransaction not available when using MDB
* [HHH-1325] - ArrayOutOfBounds expected in DatabaseMetadata.isTable when specifing schema
* [HHH-1419] - Update + Exists doesn't seem to work
* [HHH-1433] - many-to-many with additional 'with' join clause generates bad sql
* [HHH-1435] - many-to-one lazy seems to be broken in 3.1.x
* [HHH-1445] - SchemaUpdate closes shared ConnectionProvider
* [HHH-1453] - Broken exception handling in NullableType
* [HHH-1464] - QueryException from Query.getReturnAliases when query uses "fetch"
* [HHH-1486] - Concurrent access issues with both SoftLimitMRUCache and SimpleMRUCache
* [HHH-1489] - mapped composite is is always assumed as transient
* [HHH-1508] - Session.createQuery() should not flush the session
* [HHH-1531] - NPE with many-to-many and property-ref
* [HHH-1546] - generated version properties fail with multiple actions per flush
* [HHH-1430] - More complete TransactionManager in GlassFish (SunOne 9) and 8
* [HHH-1516] - support DataDirect standard jdbc stored procedures
* [HHH-1520] - with clause with implied joins within an explicit join
* [HHH-1526] - Improved DTDEntityResolver
* [HHH-1540] - Better Error Feedback In CollectionEntry.postFlush(PersistentCollection)
* [HHH-1555] - ConnectionReleaseMode.AFTER_STATEMENT and flushes
** New Feature
* [HHH-1251] - Avoid replicating the clearing of TreeCache on SessionFactory..close()
Hibernate 3.1.3 can be downloaded from here.
Recommend the tutorial