EJB Tutorial
EJB Useful Resources
Selected Reading
- EJB - Packaging Applications
- EJB - Web Services
- EJB - Exception Handling
- EJB - Query Language
- EJB - Access Database
- EJB - Entity Relationships
- EJB - JNDI Bindings
- EJB - Security
- EJB - Transactions
- EJB - Blobs/Clobs
- EJB - Embeddable Objects
- EJB - Interceptors
- EJB - Dependency Injection
- EJB - Timer Service
- EJB - Callbacks
- EJB - Annotations
- EJB - Message Driven Beans
- EJB - Persistence
- EJB - Stateful Bean
- EJB - Stateless Bean
- EJB - Create Application
- EJB - Environment Setup
- EJB - Overview
- EJB - Home
EJB Useful Resources
Selected Reading
- Who is Who
- Computer Glossary
- HR Interview Questions
- Effective Resume Writing
- Questions and Answers
- UPSC IAS Exams Notes
EJB - Overview
EJB - Overview
EJB stands for Enterprise Java Beans. EJB is an essential part of a J2EE platform. J2EE platform has component based architecture to provide multi-tiered, distributed and highly transactional features to enterprise level apppcations.
EJB provides an architecture to develop and deploy component based enterprise apppcations considering robustness, high scalabipty, and high performance. An EJB apppcation can be deployed on any of the apppcation server comppant with the J2EE 1.3 standard specification.
We ll be discussing EJB 3.0 in detail in this tutorial.
Types
EJB is primarily spanided into three categories; following table psts their names with brief descriptions −
| S.No | Type & Description |
|---|---|
| 1 |
Session Bean Session bean stores data of a particular user for a single session. It can be or . It is less resource intensive as compared to entity bean. Session bean gets destroyed as soon as user session terminates. |
| 2 |
Entity Bean represent persistent data storage. User data can be saved to database via entity beans and later on can be retrieved from the database in the entity bean. |
| 3 |
Message Driven Bean are used in context of JMS (Java Messaging Service). Message Driven Beans can consumes JMS messages from external entities and act accordingly. |
Benefits
Following are the important benefits of EJB −
Simppfied development of large-scale enterprise level apppcation.
Apppcation Server/EJB container provides most of the system level services pke transaction handpng, logging, load balancing, persistence mechanism, exception handpng, and so on. Developer has to focus only on business logic of the apppcation.
EJB container manages pfe cycle of EJB instances, thus developer needs not to worry about when to create/delete EJB objects.