What is EJB?
The EJB is a component software architecture from Sun Microsystems and it is used for building Java applications. They use a container that provides common functions which include security and transaction support. It further delivers a consistent interface to all the applications that are present, and this is regardless of the type of server. It is an essential part of a J2EE platform. The architecture being multi-tiered, distributed and has highly transactional features on an enterprise level. The EJB is an architecture that is used for setting up different program components that are written in Java programming language. These run on server parts of the client-server model. It is built on JavaBeans technology which can be used for distributing program components on the client’s network. An important advantage of JavaBeans is that it is able to control change at the server itself. There is no need of having to update the individual computer with a client whenever a new program component is added or if it is being changed. It also helps in reusing multiple applications. In order to deploy a component, it should be part of a particular container.
In order to understand EJB, it is important to know how applications use EJBs. Enterprise JavaBeans have different beans which can be used for different sessions and entities. A session bean instance serves one client at a time. The session beans can be of two types. They are being stateful and stateless. A stateless session does not need to store any session or client information. It may or may not contain states specific to a client. A stateless session can store state for a duration of method invocation. When a method completes then this issue is not retained. A stateful session maintains all information which reflects the interaction between the bean and client across methods and transactions. It can manage interactions between clients and different enterprise beans. It also has an entity which represents a set of persistent data which is usually stored in the database.
How does EJB make working so easy?
EJB does simplify the process of development of an entity and session beans. This is possible because of its simplified model and by the leveraging and well-known artifacts like POJOs and the different interfaces. It also has a new EntityManager API which makes changes to business methods and does not require any specifications. All these features also make maintaining it easier.
What can you do with EJB?
The Enterprise JavaBeans are Java classes which have annotations which help in creating business logic for different applications. With this, it also provides additional advantages of below services which are provided by EJB. These advantages are:
- Clustering: By this, you can deploy it on any clustering environment.
- Concurrency: All EJBs are instantiated through a different pool of objects.
- Connection Pool to database: All the pools created can be accessed by EJBs.
- Security: JAAS is used for security of all EJBs.
- Scheduling: It has a timer service which enables the user to implement tasks and further execute them.
Working with EJB
EJB has different containers which help in easy development of applications. The application server invokes servlets and Java Server pages. The other half is how EJBs locate and work with the protocol which helps in accessing these. To call an EJB it should be connected to a naming service of a remote application server. This naming server runs different objects on the server. Then the EJB is called which helps in connecting the EJBs to the naming service. It is to be handled how EJB can call its methods and work with it. It can add information to a message queue and then the data is saved to a database.
Listing a few advantages of EJB as below:
- EJBs have remote access capabilities which enable clustering of data which ensures scalability.
- It allows usage of attributes which makes annotation-based programming easier.
- They can be cached and pooled whenever required and the containers that are a present help in managing EJB cycles.
- It provides free security.
- It supports object-oriented concepts which make inheritance possible.
- It also provides declarative transactions.
In order to use EJB the skills that are needed include the programmer having knowledge of Java. With Java, it is an additional advantage for the programmer if they know servlets, J2EE and Oracle SQL architecture. It would make it easier to learn and know things in EJB properly.
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Why should we use EJB?
It should be used as it has many advantages. It provides services like clustering, concurrency, running transactions through JTA, security and schedule services. With all this being handy applications can be easily created to design and implement the business logic.
After C++, the next big thing that happened in the IT industry was JAVA. Java created many opportunities in IT. With the advent of Java came many other technologies which include EJB. It has a great scope in the market as it helps in creating applications easily and fast. With the features of containers, entities, and sessions it is sure to stay in the market.
Why do we need EJB?
Java being the talk of the town ever since its inception, Java developers are clamoring about EJB. It brings many services which highlight it. Due to its distributed nature, data should be in the serialized and deserialized format which enables easy communication between a client and server.
Who is the right audience for learning EJB technologies?
The people who have knowledge about Java, J2EE, and servlets should opt for learning EJB. It simplifies the process of creating various applications.
How this technology will help you in career growth?
Learning EJB will give you a cutting edge in your career. EJB being fast and reliable is famous in the market and if you are a Java professional you can easily learn EJB and start working on it. EJB will help you learn about client-server architecture and help you in getting to know about containers.
Enterprise JavaBean is a bean which helps in creating stateful and stateless sessions. The data may or may not be stored in the database. It also provides entities and containers which help in fast performance. As a result, it is a software which helps you to understand Java well and makes it easier to create applications.
This has been a guide to What is EJB. Here we discussed the Basic Concept, Required Skills, career growth and Advantages of EJB. You can also go through our other suggested articles to learn more –