Mumbai University > Information Technology > Sem 6 > Distributed System

Marks: 5Marks

EJB (Enterprise Java Beans) is a server-side component that executes specific business logic.

It enables development and deployment of component based, robust, highly scalable & transactional business application.

EJB Server :

It provides execution environment for server components.

It hosts EJB containers.

EJB Container:

It serves as interface EJB and Outside World.

Container hosts following components:

EJB Object: A client invokes beans instance through EJB Object. It is called Request Interceptor.

Remote Interface: It duplicates machines of bean class.

Home Object: It is the object factory bean where client can create or destroy object.

Home Interface: It provides machine for creating and destroying, finding bean object.

Local Interface: It is used instead of EJB objects for faster access.

The type of container depends on beans they contains i.e either transient or persistent beans.

Enterprise Beans:

They are EJB Components that encapsulates business functionalities in an application.

Container provides security to enterprise beans.

Types of Enterprise Beans:

• Session Beans(Synchronous)

• Message Driven(Asynchronous)

• Entity Beans (Data/Records in DB).

EJB Client:

It makes use of EJB beans to perform the operations.

Client locates the container using JNDI (Java Naming & Directory Interface)

Then the client invokes JB Beans machines through container.

Deployment Descriptor:

It lists the bean properties and elements like :

• JNDI Name for Bean.

• Home and Remote Interface.

• Bean Implementation Class.

• Environment Variables.

• Access Rules or Rights.

• Beans Management, Etc.