Today, in the fast-moving and highly demanding world of e-commerce and Information Technology (IT), there is a tremendous need for low-cost, distributed applications (especially transactional applications) for enterprises. These distributed enterprise applications must be designed, implemented, and deployed in less time, with few resources and greater speed.
Fortunately, the Java 2 Enterprise Edition (J2EE) provides a component-based technology for the design, development, assembly, and deployment of low-cost and fast-track enterprise applications. The purpose of J2EE is to simplify the design and implementation of distributed enterprise applications. J2EE offers the following functionalities:
- Multi-tiered distributed application model
- Reusable components
- Flexible transaction control
- Web services support through integrated data interchange on Extensible Markup Language (XML)-based open standards and protocols
- Unified security model
Since J2EE solutions are basically Java-based, they are platform-independent and are not tied to a specific vendor or customer. Customers and vendors are free to select from a wide variety of products and components.
J2EE is not a single technology; it consists of a large set of technologies, some of which are mentioned as follows:
- Enterprise JavaBeans (EJB)
- Java Servlets
- Java Server Pages (JSP)
- Java Message Service (JMS)
- Java Naming and Directory Interface (JNDI)
- Java-XML
- J2EE Connector Architecture
- Java Mail
- Java DataBase Connectivity (JDBC)
- Remote Method Invocation (RMI)
- CORBA
- RMI-IIOP
We have already covered some of these technologies in the previous chapters. In this chapter, we shall discuss some other J2EE technologies, especially, JavaBean and EJB. In Chapter 21, an introduction to JavaBean technology was given. Since JavaBean is the fundamental component technology and is a basic building block of EJB, we must discuss this technology in detail.
Source: Uttam Kumar Roy (2015), Advanced Java programming, Oxford University Press.