EJB (Enterprise Java Bean) is used to develop scalable, robust and secured enterprise applications in java.
Unlike RMI, middleware services such as security, transaction management etc. are provided by EJB Container to all EJB applications.
The current version of EJB is EJB 3.2. The development of EJB 3 is faster than EJB 2 because of simplicity and annotations such as @EJB, @Stateless, @Stateful, @ModelDriven, @PreDestroy, @PostConstruct etc.
Topics of EJB Specification
The topics of EJB specifications covered by javatpoint is given below.
What is enterprise java beans(EJB) and what are the advantages of EJB?
The session bean represents the business logic. It may be stateless, stateful or singleton.
What is stateless session bean, its lifecycle and example.
What is stateful session bean, its lifecycle and example.
How to create robust and asynchronous message for distributed applications. What are messaging domains?
What is Java Messsage Service and what are the advantages of JMS.
What is JMS Queue? It is used for peer to peer messaging where a single message is delivered to only one receiver.
What is JMS Topic? It is also known as Publisher and Subscriber model where a single message is delivered to all the subscribers.
A MDB is a JMS client that is invoked by passing message. It is deployed on the application server.
In EJB 3.2, it is deprecated. Now it is replaced with JPA.