Google returns many results, including this and this blog posts. The summary (copied from the former) is:
- Added support for persistently ordered lists using OrderColumn and provider-managed ordering column
- Defined support for foreign key mapping strategy for unidirectional one-to-many relationships
- Added clear method to EntityManager interface to allow entities to be evicted from the persistence context; added CLEAR cascade option.
- Added Cache interface.
- Added support for pessimistic locking and new lock mode types.
- Added overloaded find and refresh methods added to support locking with standardized and vendor-specific properties and hints.
- Added standardized hint javax.persistence.lock.timeout for use in locking configuration.
- Added the standardized properties javax.persistence.jdbc.driver, javax.persistence.jdbc.url, javax.persistence.jdbc.user, javax.persistence.jdbc.password for use in persistence unit and entity manager factory configuration.
- Added Query getNamedParameters and getPositionalParameters methods.