Enterprise Java Beans – EJB

Enterprise Java Beans (EJB) is a technology to create complex and scalable business applications. Developers use EJB and the Java programming language to build server-side components that handle business logic, such as transactions and data management.

Enterprise applications differ significantly from regular software applications, such as desktop software that supports one user at a time.

For example, enterprise applications must handle large amounts of data and transactions over the Internet from 10s of thousands of users (or more) simultaneously and have strict security requirements.

EJB provides a standardized architecture for creating, deploying, and managing such server-side components in Java. 

A Bit of Context

EJB has faced criticism due to its complexity and overhead. It requires significant configuration and setup, and developers must follow strict rules and guidelines to build EJB components.

EJB is also known to be resource-intensive, requiring powerful servers and infrastructure to handle large-scale applications.

In recent years, lightweight frameworks and microservices have become popular as they offer a more flexible and agile approach to enterprise application development.

However, EJB is still widely used in many enterprise applications, especially those that require strict security and transaction management.

EJB Architecture

The EJB architecture includes three main components: session beans, entity beans, and message-driven beans.

1. Session Beans: Session beans are server-side components that contain the business logic of the software. Depending on the application requirements, they can be stateless, stateful, or singleton. Stateless session beans are used when the business logic is independent of any client state, while stateful session beans are used when the business logic depends on the client state. Finally, Singleton session beans support the entire application with just one instance of a bean.
2. Entity Beans: Entity beans manage data in a transactional manner to ensure data consistency and integrity. They are persistent objects that represent data stored in a database. They can be either container-managed or bean-managed. Container-managed entity beans are easier to develop because the container handles most of the persistence logic. In contrast, bean-managed entity beans require more development effort because the developer has to handle the persistence logic.
3. Message-Driven Beans: Message-driven beans process messages asynchronously, enabling applications to handle events and messages in real-time. They are similar to session beans, but instead of being accessed by clients, they are triggered by messages sent to a message queue or topic.

EJB Benefits

EJB provides several benefits for enterprise applications, such as:

1. Scalability: EJB components can be deployed on multiple servers, enabling applications to handle many concurrent users.
2. Security: EJB provides built-in security features such as authentication, authorization, and encryption to ensure the application’s security.
3. Transaction Management: EJB components provide transactional support, ensuring data consistency and integrity.
4. Reusability: EJB components can be reused across multiple applications, reducing development time and cost.

Conclusion

EJB is a powerful technology for building enterprise applications, with a standardized approach for developing scalable, distributed, and secure components.

Although EJB requires some extra effort and resources to set up, it can result in more efficient and maintainable applications in the long run. 

What are EJBs? – 12 mins