What is EJB in Java and How to Implement it?

If you are wondering what EJB is, then you have landed at the right place. EJB stands for Enterprise Java beans. It is one of the several Java APIs for standard manufacture of enterprise software. In this tutorial, you will get a complete insight on this topic.

The agenda for this article is mentioned below:

• What is EJB in Java?
• What are the functions of EJB?
• What are the types of EJB
• When to use EJB?
• Advantages of EJB
• Disadvantages of EJB

Let’s begin!

What is EJB in Java?

EJB is server-side software that helps to summarizes the business logic of a certain application. EJB was provided by sun micro-systems in order to develop robust, secure applications. The EJB enumeration is a subset of the Java EE enumeration. Enterprise Java beans managers concerns such as endurance security transnational property that would leave the programmers in a position to focus more on parts of the enterprise software at hand.

After understanding the meaning of enterprise Java beans, let us move towards understanding the functions.

What are the functions of EJB?

Whenever you have to run an EJB application, an application server is needed, for example, Glass-fish, Web-logic, Web-sphere etc. The functions it performs are as follows:

• Life-cycle management
• Security
• Transaction management
• Object pooling

There are different types of enterprise Java beans. I will discuss them with you now.

What are the types of EJB?

There are several types of enterprise Java beans. The list can be seen below:

1. Session beans
2. Entity beans
3. Message-driven beans

Session beans: these are non-persistent enterprise beans. There are two kinds of session beans:
Stateful: a stateful session Bean maintains client-specific session information across several transactions. It exists for the duration of a single client/server session.
Stateless: a stateless session bean is an old bye their container so that they can easily handle several requests from clients.

Entity beans: These beans contain persistent data and it can be saved in the data source. There are two types:

• Container managed persistence: these entity beans assign their persistence to the EJB container
• Bean managed persistence: these entity beans manage their own persistence.

Message-driven beans: Message-driven beans are enterprise beans that receive and process Java message service messages. They can be accessed only through messaging. They do not have interfaces. Asynchronous communication between the queue and the listener takes place.

These were the different types of enterprise Java beans. Next topic is the usage of EJB. Let us begin!

When to use EJB?

There are certain cases when you can use enterprise Java beans. Have a look:

• When your application needs remote access.
• When your application is business logic.
• When your application needs to be scalable.

Moving forward, let’s study the advantages of EJB.

Advantages of EJB

I have mentioned a few advantages of EJB which are as follows:

• EJB is an API, hence the application’s build on EJB can run on Java EE web application server.
• The EJB developer focuses on solving business problems and business logic.
• Java beans are portable components that help the JAVA application assembler to formulate new applications for the already existing JavaBeans.
• EJB container helps in providing system-level services to enterprise Java beans.
• EJB contains business logic hence the front end developer can focus on the presentation of the client interface.
• It provides simplified development of large scale enterprise level application.

These were few advantages now let us understand the disadvantages of enterprise Java beans.

Disadvantages of EJB

Here is a list showcasing the disadvantages of enterprise Java beans:

• The specification of EJB is pretty complicated and large
• It creates costly and complex solutions
• Abundant resources are utilized and they possess a lot of artefacts
• It takes time for development
• Continuous revision of the specifications takes place
• There are more complex cities than straight Java classes

With this, we come to the end of this EJB in Java article. I hope you have understood what is EJB in Java and how to implement it.

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