The Java Persistence API (JPA) is an object relational mapping API. Object relational mapping tools help us automate mapping Java objects to relational database tables. Earlier versions of J2EE used Entity Beans as the standard approach for object relational mapping. Entity Beans attempted to keep the data in memory always synchronized with database data, a good idea in theory, however, in practice this feature resulted in poorly performing applications.

Several object relational mapping APIs were developed to overcome the limitations of Entity Beans, such as Hibernate, iBatis, Cayenne, and Toplink among others.

With Java EE 5, Entity Beans were deprecated in favor of JPA. JPA took ideas from several object relational mapping tools and incorporated them into the standard. As we will see in this chapter NetBeans has several features that make development with JPA a breeze.

The following topics will be covered: