Kulkarni - Java EE 8 development with Eclipse

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First published: December 2012
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Java Enterprise Edition (JEE, which was earlier called J2EE) has been around for many years now. It is a very robust platform for developing enterprise applications. J2EE was first released in 1999, but underwent major changes with the release of version 5 in 2006. Since version 5, it has been renamed Java Enterprise Edition (JEE). Recent versions of JEE have made developing a multi-tier distributed application a lot easier. J2EE had focused on core services and had left the tasks that made application development easier to external frameworks, for example, MVC and persistent frameworks. But JEE has brought many of these frameworks into the core services. Along with the support for annotations, these services simplify application development to a large extent.

Any runtime technology is not good without good development tools. The Integrated Development Environment (IDE) plays a major part in developing applications faster, and Eclipse provides just that for JEE. Not only do you get good code editing support in Eclipse, but you also get support for build, unit testing, version control, and many other tasks important in different phases of software application development.

In this chapter, we are going to cover the following topics:

• Introduction to different technologies in JEE
• Introduction to the Eclipse development environment
• Installation and configuration of some of the frequently used software in this book, for example, JEE servers, Eclipse IDE, and MySQL Database Server

The goal of this book is to show how you can efficiently develop JEE applications using Eclipse by using many of its features during different phases of the application development. But first, here is a brief introduction to JEE and Eclipse.

JEE is a collection of many of the Java Community Process ( https://www.jcp.org ) programs. Currently, JEE is in Version 8. However, different specifications of JEE are at their own different versions.

JEE specifications can be broadly classified into the following groups:

• Presentation layer
• Business layer
• Enterprise integration layer

Note that JEE specification does not necessarily classify APIs in the preceding broad groups, but such classification could help in better understanding the purpose of the different specifications and APIs in JEE.

Before we see APIs in each of these categories, let's understand a typical JEE web application flow, as shown in the following diagram, and where each of the preceding layers fits in:

Requests start from the clients. A client can be any application requesting services from a remote applicationfor example, it could be the browser or a desktop application. The request is first received by the web server at the destination. Examples of web servers include Apache web server, IIS, and nginx. If it is a request for static content, then it is served by the web server(s). However, a dynamic request typically requires an application server to process. JEE servers are such application servers that handle dynamic requests. Most JEE specification APIs execute in the application server. Examples of JEE application servers are WebSphere, GlassFish, and WildFly.

Most non-trivial JEE applications access external systems, such as a database or Enterprise Integration Server (EIS), for accessing data and process it. A response is returned from the application server to the web server and then to the clients.