Wednesday Mar 12, 2014

JPA 2.1 Entity Graphs

Entity Graphs are a very important but somewhat underrated enhancement in JPA 2.1/Java EE 7. The feature significantly improves the ability to load/fetch JPA data beyond the very coarse grained mechanism of traditional ORM lazy and eager loading. Applied correctly, entity graphs could significantly improve application performance in still a fairly elegant way. Hantsy Bai does an excellent job explaining the basics of JPA 2.1 entity graphs in a recent blog post. He demonstrates how to define an entity graph using annotations or programatically, using the entity graph in a simple query and the basic value proposition for entity graphs. Linda DeMichiel dedicated a good amount of time explaining entity graphs during her JavaOne 2013 talk on JPA 2.1 (video below).

The official Java EE 7 tutorial also has a pretty decent section on entity graphs. It is definitely worth your time to understand the feature well and apply it in your JPA applications.

Wednesday Nov 20, 2013

JPA 2.1 Type Converters

Somewhat surprisingly, JPA 2.1 appears to be one of the APIs that seems to get lost in the Java EE 7 buzz. Although it is a point release JPA 2.1 includes a fairly large number of very important changes such as schema generation, entity graphs, support for stored procedures, unsynchronized persistence contexts, entity converters, and much, much more. In a code driven post Thorben Janssen discusses one of these changes - entity converters. There's also the 20-minute JPA 2.1 presentation by specification lead Linda Demichiel on the GlassFish videos YouTube channel:

More recently, Linda presented a JavaOne 2013 technical session titled Java Persistence 2.1. Stay tuned to Parleys.com for video of the session to be posted.