Spring JPA is a part of the Spring Data project that makes it easy to quickly implement JPA-based repositories.
IntelliJ IDEA 11 recognizes repositories, 
provides quick navigation through the code,
adds advanced completion, error highlighting and quick fixes.
Download IntelliJ IDEA 11 Beta and try it.
In IntelliJ IDEA 10 a new JPA Console is added to existing Hibernate and Database consoles. Now you can run and test your JPA queries in a target environment of your application.
Both Hibernate and JPA consoles are available if applicable.
Note the new “Run Query in Console” Intention Action that is now available on all the supported types of queries: JPA QL, Hibernate QL and SQL. It allows you to quickly run a query directly from the editor in a corresponding console either new or already running.
The upcoming IntelliJ IDEA 8.1.1 includes a new option to generate separate XML mapping per entity.
With IntelliJ IDEA you can quickly generate persistence mappings from any database schema. This feature is not so easy to find, so here’s the tip:
In IntelliJ IDEA HQL console can be used with pure JPA facets (as well as with Hibernate facets) to run JPAQL and HQL queries. All you need is Hibernate libraries and JDBC driver in a module classpath. If persistence.xml contains no Hibernate-specific database connection options, it should be mapped to an existing data source via JPA facet settings.
Tip: HQL console can also be used to generate DDL statements for JPA and Hibernate mappings via its Generate DDL command.
Update: If a Persistence Unit or Session Factory is mapped to a valid local Data Source there is no need to specify JDBC driver jars in a module classpath (Since 8.1.1).
In IntelliJ IDEA you can quickly navigate within JPA/Hibernate ER-Diagram using the File Structure Popup (press Ctrl+F12, or invoke View menu, File Structure Popup command):
Tweets about IntelliJ IDEA
