Introduction
Enterprise Bean is a server-side component that encapsulates business logics.
Why Enterprise Bean?
- Because application service provides a lot of system-level service. Developers can concentrate logic in Enterprise Bean
- Server-side Enterprise Bean is responsible for business logic while client-side component can focus on presentation.
The application server provide services including transaction handling, logging, load balancing, persistence and exception handling.
Types of Enterprise Bean
- Session Bean
- Message Driven Bean
The Session Bean performs task for client while Message-Driven Bean acts as listener for particular message (MQ).
Session Bean
Session bean could be further classified as two types of bean
- Stateful Bean
- Stateless Bean
Stateful bean contain state information while Stateless bean doest not.
Client Types
The session bean could be access by different clients.
Client | Requirement |
Local | Same Application(One is Web Modules and Another is EJB Modules) |
Remote | Can be Different Machine, Different JVM |
Web Service | Access EJB through correct Protocol |
Example List