The Enterprise Java Beans Component and container

The Enterprise Java Beans Component and container

The Enterprise Java Beans Component

An Enterprise JavaBean is a component, just like a traditional JavaBean. Enterprise
JavaBeans execute within an EJB container, which in turn executes within an EJB server.

INSTALLING AND RUNNING APPLICATION SERVER FOR EJB  

Depending on the requirements of the organisation or company, one may select an
appropriate Application server. If organisation’s business processes span hundreds or

CHOOSING ENTITY BEANS OR STATEFUL SESSION BEANS

CHOOSING ENTITY BEANS OR STATEFULSESSION BEANS

 Now, we will learn when and where we should use entity beans or stateful session beans. The architect of the application chooses how to map the business entities and processes to

DIFFERENCE BETWEEN SESSION BEANS AND ENTITY BEANS

DIFFERENCE BETWEEN SESSION BEANS AND ENTITY BEANS

To understand whether a business process or business entity should be implemented as a

stateful session bean or an entity bean, it is important to understand the life-cycle and

DISADVANTAGE OR RESTRICTIONS OF EJB

DISADVANTAGE OR RESTRICTIONS OF EJB

Enterprise Java Beans have several restrictions, which they must adhere to:
1. They cannot create or manage threads.
2. They cannot access threads using the java.io package.
3. They cannot operate directly with sockets.
4. They cannot load native libraries.
5. They cannot use the AWT to interact with the user.
6. They can only pass objects and values which are compatible with RMI/IIOP.
7. They must supply a public no argument constructor.
8. Methods cannot be static or final.
9. There are more minor restrictions.

But following can be done with EJB:
1. Subclass another class.
2. Interfaces can extend other interfaces, which are descendants of EJBObject or
EJBHome.
3. Helper methods can pass any kind of parameters or return types within the EJB.
4. Helper methods can be any kind of visibility

SERVICES OFFERED BY EJB

SERVICES OFFERED BY EJB

JSP, Servlets and JavaBeans and EJBs have their own web container. The container of
EJB provides certain built-in services to EJBs, which is used by EJBs to perform different

ARCHITECTURE OF AN EJB/ CLIENT SYSTEM

ARCHITECTURE OF AN EJB/ CLIENT SYSTEM

There are various architectures of EJB (J2EE) available which are used for various
purposes. J2EE is a standard architecture specifically oriented to the development and