Hi friend,

The Java Persistence API, sometimes referred to as JPA, is a Java programming language framework
that allows developers to manage relational data in Java Platform, Standard Edition and Java Platform,
Enterprise Edition applications.

Persistence consists of three areas:

* the API, defined in the javax.persistence package
* the Java Persistence Query Language
* object/relational metadata

Hibernate is an Open_source Object-relational_mapping framework for Java


hibernate is a ORM(object relation mapping ) tool which can be used for creating a mapping between plain
java bean objects (POJO) and a persitent storage (rdbms).
The EJB 3.0 specififcation is divided into two parts the first which deals with session and MDBs and
the second which deals with persistence and entity beans.
The latter part is called JPA(java persistance API ).
HIbernate 3.0 implements the JPA specification.
EJB 2.1 is a specification for defining loosely coupled reusable business componenets.ans 2 & 3 )
EJB 2.1 and hibernate serve two different purposes. Hibernate can be co related with the entity beans in EJB 2.1.
HIbernate offers far more extensive features then plain entity beans.still
there are no containers (applicaiton servers) available which fully implement the EJB 3.0 specification.
depending upon the buisness needs hibernate framework can be used in conjuction with EJB2.1 to achieve the JPA abstraction.

For more information on EJB 3.0 visit to :

http://www.roseindia.net/java/jee5/what-is-ejb3.shtml

Thanks