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JPA Introduction
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What is JPA ?
JPA is a specification .
Hibernate is an implementation of this specification.
Two important principles in this specification are :
JPA engines should be pluggable, which means you should be able to take out one product and replace it with another if you aren’t satisfied—even if you want to stay with the same EJB
3.0 container JPA engines should be able to run outside of an EJB
3.0 runtime environment, without a container in plain Java.
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Modules in Hibernate
Hibernate Core
Hibernate Annotations
Hibernate EntityManager
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Hibernate Core
It is the base service for persistence, with its native API and its mapping metadata stored in XML files.
It has a query language called HQL , as well as programmatic query interfaces for Criteria and Example queries.
Hibernate Core is the foundation and the platform all other modules are built on.