Jack

• Feb 28th, 2006

 

Current version right Now is EJB3.0[Jan 2006]

EJB 3.0 Features
Session Beans
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POJO bean class - No requirement for implementing javax.ejb.SessionBean interfaces
POJI interface - No requirement for extending javax.ejb.EJBObject or javax.ejb.EJBLocalObject interfaces
Optional Home interface
Metadata Annotations
Simplified Exception Handling
Dependency Injection for EJBContext, Resources and environment references
Enhanced lifecycle methods and call back listener classes
Interceptor methods and classes
Step wise migration for EJB 2.1 Session Beans to EJB 3.0
JDK 1.4 support with XML deployment descriptors

Entity Beans
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Light weight persistence model
No component interfaces
EntityManager API
Metadata Annotations for O-R Mapping
Default Mappings
Query Language enhancements (Bulk update, named parameter)
Callback Listeners
Outside J2EE container

Message Driven Beans
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POJO bean class - No requirement for implementing javax.ejb.MessageDriven interfaces
Metadata Annotations
Dependency Injection for EJBContext, Resources and environment references
Enhanced lifecycle methods and call back listener classes
JDK 1.4 support with XML deployment descriptors

EJB 2.1 Features
Message-driven beans (MDBs): can now accept messages from sources other than JMS.
EJB query language (EJB-QL): many new functions are added to this language: ORDER BY, AVG, MIN, MAX, SUM, COUNT, and MOD.
Support for Web services: stateless session beans can be invoked over SOAP/HTTP. Also, an EJB can easily access a Web service using the new service reference.
EJB timer service: a new event-based mechanism for invoking EJBs at specific times.
Many small changes: support for the latest versions of Java specifications, XML schema, and message destinations.