JPA advantages

Java Persistence API

• provide a light-weight POJO persistence API for object/relational mappining.

The Java Persistence API incorporates support for many of the features that EJB developers have been asking for, including

• Support for improved object modeling,
• Inheritance,
• Polymorphism,
• Expanded query language, and
• Rich metadata for the specification of object/relational mapping.

http://www.ibm.com/developerworks/websphere/library/techarticles/0707_barcia/0707_barcia.html?S_TACT=105AGX10&S_CMP=WASCE#j7

http://java.sun.com/developer/technicalArticles/J2EE/jpa/