This document discusses entity beans in Java. It defines entity beans as enterprise beans that represent persistent data stored in a database. Each entity bean instance corresponds to a row in a database table. The EJB container is responsible for loading data into entity bean instances and storing it back in the database. Entity beans are persistent, meaning their state exists across client sessions. They also support shared access, with multiple clients accessing the same data through separate entity bean instances. The document outlines the characteristics and lifecycle of entity beans.

1. ENTITY BEAN IN JAVA
Hiren Jamod
Department Of ComputerScience
Saurastra University-Rajkot

2. ENTITY BEANS
 Enterprise Beans which represent persistent
data stored in a storage medium, such as a
relational database.
 Persists across multiple sessions and can be
accessed by multiple clients.
 Each instance of the entity bean represent a row
in the table
 EJB container creates instances of an entity bean
and is responsible for loading data in an instance
and storing the information (data) back into the
database.

3. ENTITY BEANS
 The persistent mechanisms that enable you to
perform these database manipulations, such as
serialization, Object/Relationship (O/R) mapping
to a relational database and support for JDBC
are built-in the entity bean model

4. CHARACTERISTICS
Persistence
 Implies that its state exists even after a client stops
accessing an application
 The persistent data remain intact even after the
storage shuts down
Shared Access
 Multiple clients can share one entity bean by using
separate instances of the entity bean
 EJB Container maintains data consistency by
synchronizing entity bean instances with the
database
 To maintain data consistency, the entity beans work
within a transaction

5. CHARACTERISTICS
Primary Key
 Each Entity bean has unique identifier; is known
as Primary Key that enables the client to locate
the exact entity bean
Relationships
 Like the data of a relational database, the entity
beans are also elated to each other

6. LIFE CYCLE OF ENTITY BEANS

7. LIFE CYCLE OF ENTITY BEANS
 Initially, the beans do not exist
 When the Application server this stage to the Pooled
stage
 When the server is first started, several bean
instances are created and placed in the pool.
 A bean instance in the pooled state is not ties to
particular data
 At this stage, the beans are referred as passivated.
 The bean remains in this stage till the client does
not make a request for it or the container does not
activate it.

8. LIFE CYCLE OF ENTITY BEANS
 The bean’s business methods can be invoked
when the bean is at the ready stage.
 It remains at this stage till the client calls its
remove method or the container passiveness it if
the bean has been lying idle for sometimes

9. EJB SOURCE CODE
 Home Interface (extends EJBHome)
 Create - Find (for Entity)
 Factory Pattern
 Remote Interface (EJBObject)
 “Business Methods”
 Proxy Pattern
 Bean Class (EntityBean)
 Deployment descriptor (ejb-jar.xml)

10. CRAETE APPLICATION

11. GIVE NAME OF CRAETE APPLICATION

12. ADD SESSION BEAN

13. GIVE NAME OF SESSION BEAN

14. ADD PERSISTENCE UNIT

15. GIVE NAME PERSISTENCE UNIT

16. ADD ENTITY CLASS

17. ADD REFERENCE INTO WEB.XML

18. DECLER INTERFACE

19. DEFINE INTERFACE AND OVERRIDE
METHOD

20. DEFINE ENTITY BEANCLASS

21. DEFINE INDEX PAGE

22. DEFINE INDEX PAGE

23. DEFINE INDEX PAGE

24. DEFINE INDEX PAGE

25. SPECIAL THANKS T0 AMIT SIR
TO GIVE ME OPPORTUNITY TO REPRESENT MY
PRESENTATION.
BY HIREN JAMOD