Java EE 5 Application Components

Java EE 5 simplifies development of enterprise applications by basing them on standardized, modular components, providing a complete set of services to those components, and handling many details of application behavior automatically, without complex programming. Prominent Java EE components include:

• Client Application

• Web Application

• Enterprise Java Bean (EJB)

• Connector

• Enterprise Application Archive (EAR)

• Annotations

Java EE components are packaged separately and bundled into a Java EE application for deployment. Each component, its related files such as GIF and HTML files or server-side utility classes, and a deployment descriptor are assembled into a module and added to the Java EE application. A Java EE application is composed of one or more enterprise bean(s), Web, or application client component modules. The final enterprise solution can use one Java EE application or be made up of two or more Java EE applications, depending on design requirements.

A Java EE application and each of its modules has its own deployment descriptor. A deployment descriptor is an XML document with an .xml extension that describes a component’s deployment settings.

A Java EE application with all of its modules is delivered in an Enterprise Archive (EAR) file. An EAR file is a standard Java Archive (JAR) file with an .ear extension. The EAR file contains EJB JAR files, application client JAR files and/or Web Archive (WAR) files.

The migration process is concerned with moving Java EE application components, modules, and files. For more information on migrating various Java EE components, refer to Chapter 6, Migrating from Other Application Servers to Sun Java System Application Server 9.

For more information on Java EE, see:

• Java EE 5 specification

• Java EE 5 website