Understanding EJB 3.0 Java Persistence API

The Java 2 Enterprise Edition(J2EE) Enterprise JavaBeans (EJB) are a component architecture that you use to develop and deploy object-oriented, distributed, enterprise-scale applications. An application written according to the Enterprise JavaBeans architecture is scalable, transactional, and secure.

The EJB 3.0 Java Persistence API (JPA) improves the EJB architecture by reducing its complexity through the use of metadata (annotations) and specifying programmatic defaults of that metadata.

Mapping an entity