Programming Tutorials

Types of EJB

By: aathishankaran  

Types of EJB:

 

There are three types of Enterprise Java Beans namely:

 

v    Session Beans

v    Entity Beans

v    Message driven beans

 

1) Session Beans

 Session beans are intended to allow the application author to easily implement portions of application code in middleware and to simplify access to this code.

Session beans are divided into two types:

a)     Stateless Session Bean

b)    State full Session Bean

            a)    Stateless Session Bean

                 Stateless Session Bean is intended to be simple and “light weight” components.  The client, thereby making the server highly scalable, if required, maintains any state.  Since no state is maintained in this bean type, stateless session beans are not tied to any specific client, hence any available instance of a stateless session bean can be used to service a client.  

        b)    State full Session Bean

                State full Session Bean provides easy and transparent state management on the server side.  Because state is maintained in this bean type, the application server manages client/bean pairs.  State full session beans can access persistent resources on behalf of the client, but unlike entity beans, they do not actually represent the data.