Guide to Enterprise Java Beans - Meaning | Types | Architecture

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Enterprise Java Beans is a powerful tool for building big, strong, safe Java apps. Unlike RMI, which needs you to handle security and transactions, EJB Beans Container takes care of everything. The latest version of EJB is 3.2, and it's much easier to use than earlier versions thanks to simple coding and unique tags called annotations. Additionally, these tags make it quick and easy to create different kinds of EJB components and manage their lifecycle.

What is EJB in Java?

Enterprise beans are the core components for big Java apps. They run in the EJB container, part of the GlassFish Server. In addition, the Enterprise Java Beans container handles necessary stuff like transactions and security, so you don't have to worry about it. As a result, this makes it easy to create and use enterprise beans, which are the heart of Java apps that handle lots of data and need to be reliable.

By 1996, Java was already a favorite among programmers because it was easy to use and cleaned up after itself automatically.  However, it was starting to be used a lot in the behind-the-scenes part of computer systems. But there was a problem: most of these systems needed the same basic tools, like saving data, keeping transactions safe, and controlling how many things could happen simultaneously. Java didn't have these tools at the time. So, people started making their own, which were often only for their use and not shared with others.

Types of Enterprise Java Beans

There are three main types of EJB beans:

1. Session Bean: This is a worker that does specific tasks. There are two kinds:

• Stateful Session Bean: This remembers things about a customer and uses that information to do its job. For example, a shopping cart remembers the items a customer has chosen.
• Stateless Session Bean: This doesn't need to remember anything about a specific customer and can be used by many different customers at once.

2. Message-Driven Bean: This is a worker that waits for messages and then does something based on the message.

3. Entity Bean: This is a way to store information in a database. It's no longer used much, and has been replaced by JPA. There used to be two kinds:

• Bean Managed Persistence: The programmer had to write the code to talk to the database.
• Container Managed Persistence: The container handled the database stuff automatically.

Enterprise Java Beans Architecture

EJB is a way to build big, complex Java apps for businesses. It's based on a technology called RMI, and it uses a four-part structure: clients, a web layer, an application layer, and a data layer. As a result, this structure helps keep the app organized and easy to manage.

The EJB architecture is built on two main parts: the Application Server and the EJB Container. These two parts work together to make EJB apps possible.

Application Server

• The Outermost Layer: This is where the Container lives.
• Execution Environment: It provides the space for EJB applications to run.
• Popular Examples: WebLogic, Tomcat, JBoss, WebSphere, Wildfly, and GlassFish.
• Main Tasks:
  • It manages connections between different parts of the application.
  • Runs the processes that make up the application.
  • Connects to databases.
  • Manages other resources needed by the application.

Container

• The Second Outermost Layer: This is where Enterprise Java Beans applications live.
• Supporting Services: It provides many helpful services for EJB applications.
• Services:
  • Managing transactions and object interactions.
  • Monitoring activities and coordinating different parts of the application.
  • Providing security.
  • Managing resources efficiently.
  • Managing the life cycle of EJB applications and ensuring they work together smoothly.
  • Helping EJB applications focus on their main job of handling business logic.

What is the Use of EJB?

Enterprise Java Beans (EJBs) are tools that make building big, complex Java apps simpler. In addition, they provide an advanced environment where these apps can run. EJBs help developers in a few ways:

• Less Work for Developers: EJBs take care of things like security and transactions, so developers can focus on the important parts of the app.
• Easier for Clients: Because the logic is in the EJBs, developers who work on the part of the app that users see can focus on that without worrying about the behind-the-scenes stuff.
• Building Apps Faster: EJBs can be used in different apps, so developers can reuse them to create new apps more quickly.

Working of EJB Enterprise Java Beans?

Here, we will define the work of EJB. We already discussed the basics of EJBs which are a valuable tool for building scalable, secure, and maintainable enterprise applications. By understanding the core concepts of EJBs, developers can effectively leverage this technology to create robust and efficient applications.

EJBs: The Building Blocks of Enterprise Java Applications

Enterprise JavaBeans (EJBs) are a powerful technology within the Java EE platform that simplifies the development of large-scale, distributed enterprise applications. In addition, they provide a runtime environment for enterprise beans, which are Java components that encapsulate business logic.

The EJB Component

An EJB component is a Java class that implements business logic. In addition, it's the core of an EJB application. Unlike traditional JavaBeans, EJB components are designed to run within an EJB container, which provides various services to the component.

The EJB Container

The EJB container is a runtime environment that provides essential services to EJB components. These services include:

• Transaction management: Ensures data consistency and integrity across multiple operations.
• Security: Enforces access control and protects sensitive data.
• Persistence: Manages the persistence of EJB components and their data.
• Concurrency control: Prevents conflicts when multiple clients access the same EJB component simultaneously.
• Remote method invocation: Enables clients to access EJB components located on different machines.

The EJB Object

An EJB object is a client-side proxy that represents an EJB component. Clients interact with EJB components through EJB objects. When a client invokes a method on an EJB object, the method call is transmitted to the EJB container, which then forwards it to the appropriate EJB component.

Benefits of Using Enterprise Java Beans

After understanding the working, we will move further towards the benefits of EJB beans. 

• Portability: EJB applications are portable and can be deployed on any Java EE-compliant application server.
• Simplified development: It handles many low-level tasks, allowing developers to focus on business logic.
• Improved scalability: EJB containers can distribute EJB components across multiple servers to handle increased workloads.
• Enhanced security: EJB containers provide built-in security features to protect EJB components and their data.

What is the Difference Between Enterprise Java Bean and Spring Bean?

EJBs and Spring Beans are both used to build Java apps, but they are different in a few ways:

• Type: EJBs are like rules, while Spring is like a toolkit.
• Support: EJBs help with the back-end of apps, while Spring can help with the front-end, APIs, and newer ways of coding.
• Structure: EJBs have a specific structure, while Spring is more flexible.
• How to Build: EJBs follow a set way of building apps, while Spring is more open to different ways.
• Parts of the App: EJBs are small parts that can be used again, while Spring Beans are managed by a different system.
• Saving Data: EJBs can always be saved, but Spring Beans don't have to be.
• Starting Up: EJBs need a special way to start, while Spring Beans don't always need it.

Final Words

Enterprise Java Beans are a strong tool for building big Java apps. Additionally, they follow a set way of doing things, help with things like security, and let you use parts of the app again. If you understand how EJBs work, you can use them to make apps that are big, safe, and easy to change. But it's important to compare EJBs to other tools like Spring because each one has its advantages and disadvantages depending on what you're trying to build.

Frequently Asked Questions