Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Developer's Guide


A J2EE module is a collection of one or more J2EE components of the same container type (for example, web or EJB) with deployment descriptors of that type. One descriptor is J2EE standard, the other is Application Server specific. Types of J2EE modules are as follows:

Package definitions must be used in the source code of all modules so the class loader can properly locate the classes after the modules have been deployed.

Because the information in a deployment descriptor is declarative, it can be changed without requiring modifications to source code. At run time, the J2EE server reads this information and acts accordingly.

The Application Server also supports lifecycle modules. See Chapter 10, Developing Lifecycle Listeners for more information.

EJB JAR and Web modules can also be deployed separately, outside of any application, as in the following figure. EJB components are assembled in a JAR file with ejb-jar.xml and sun-ejb-jar.xml deployment descriptors. Web components are assembled in a WAR file with web.xml and sun-web.xml deployment descriptors. Both module types are deployed to the Application Server.

Figure 3–1 Module assembly and deployment

Figure shows EJB or Web module assembly and deployment.