Difference between Session Beans and Entity Beans in J2EE

Session beans and entity beans are two types of enterprise beans in J2EE, which are used for different purposes:

Session Beans:

Session beans are used to represent a single client's session. They are lightweight and are used to perform business logic and process a particular client's requests.

Types of Session Beans:

• Stateless Session Beans: These beans do not maintain a conversational state with the client and are suitable for high-performance, stateless operations.
• Stateful Session Beans: These beans maintain a conversational state with the client and are used when the client needs to maintain information across method calls.
• Singleton Session Beans: These are instantiated only once per application and provide a single instance shared by all clients.

Entity Beans:

Entity beans are used to represent data in the database. They are used to interact with the persistence layer and perform database operations like CRUD (Create, Read, Update, Delete).

Types of Entity Beans:

• Container-Managed Entity Beans (CMT): The container manages the lifecycle of these beans, including persistence and transaction management.
• Bean-Managed Entity Beans (BMT): The bean itself manages the lifecycle, persistence, and transaction management of these beans.

In summary, session beans are used for business logic and processing client requests, while entity beans are used for interacting with the database and managing data persistence in J2EE applications.