| Type | Description | Descriptor | Contents |
|---|
| CAR | Client application archives | application-client .xml | Thick Java client for EJBs |
| EAR | Enterprise application archive | application.xml | Other Java EE modules such as EJB-JARs. |
| EJB-JAR | EJB Java archive | ejb-jar.xml | Session beans, message-driven beans, and optionally entities. Needs a persistence.xml if entities are packaged. |
| RAR | Resource adapter archives | ra.xml | Resource adapters. |
| WAR | Web application archives | web.xml | Web application artifacts such as servlets, JSPs, JSF, static files, etc. Entities can also be packaged in this module. Needs a persistence.xml if entities are packaged. |
Java EE 5 made the deployment descriptor optional, even in the EAR. This is a departure from previous versions of Java EE, where it was mandatory. The Java EE 5.0.compliant application servers deploy by performing automatic detection based on a standard naming convention or reading the content of archives.
