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Migrating EJB 2.1 Entity and Session Beans to EJB 3.0
The nuts and bolts
Summary
So, to summarise this tutorial:
- EJB development in EJB 3.0 specification is simplified by replacing abstract bean classes with POJOs.
- Component and Home interfaces are not required in EJB 3.0.
- Deployment descriptors are replaced with metadata annotations in the bean class. Familiarity with JDK 5.0 annotations is required to migrate EJB 2.0/2.1 to EJB 3.0.
- The
EntityManager
API is used to create and find entity bean instances in EJB 3.0 instead of thecreate
, andfinder
methods in EJB 2.1. - JNDI, which is required to obtain references to resources in EJB 2.1 is replaced with the
@Resource
,@Inject
and@EJB
annotations in EJB 3.0 specification.
Deepak Vohra is a Sun Certified Java Programmer and Sun Certified Web Component Developer. Deepak is a Web developer; and has published in XML Journal, WebLogic Developer's Journal and ONJava.com.