Enterprise Java Beans Features

Enterprise Java Beans

                                                             The Enterprise Java Beans architecture is an architecture for the development and deployment of component-based business applications. 

What is component based business applications ? 

                            Application which emphasizes the "Separation of Concerns" in respect to other wide range functionality.Its a reuse based approach to defining, implementing and composing loosely coupled independent component into systems. With regard to system-wide co-ordination, components communicate with each other via interfaces. When a component offers services to the rest of the system, it adopts a provided interface that specifies the services that other components can utilize, and how they can do so.

EJB applications are:

• Scalable
• Transactional
• Multi user secure
• Can be deployed on any application server as a distributed application
• provides various system level service like security,transaction etc.

Various features are introduced in new versions of EJB , some brief points are given as:

Features in EJB 3.0 :

• Annotation used to annotate EJB application, for simplifying developer's task
• Eliminating the need for developer to provide an EJB deployment descriptor.
• JNDI access through the use of annotation,lookup and DI mechanism
• The required business interface for a session bean can be a plain Java interface rather than an EJBObject, EJBLocalObject, or java.rmi.Remote interface
• Elimination of the requirement for home interfaces for session beans.
• An interceptor facility for session beans and message-driven beans.
• Reduction of the requirements for usage of checked exceptions.
• Elimination of the requirement for the implementation of callback interfaces.

Features in EJB 3.1 :

                                   EJB 3.1 has many more features and is even easier to use,lets look into these.

• Optional Session Bean Business Interfaces
• Global JNDI Names
• Singleton Session Beans
• Asynchronous Session beans
• Easy packaging
• EJB 3.1 Embeddable Container