Packaging
ejb-jar file is used to package un-assembled enterprise beans and assembled applications.
ejb-jar file contains the enterprise bean class implementation, bean's remote interface, bean's home interface and primary key class, and the META-INF/ejb-jar.xml file for the deployment descriptor.
The deployment descriptor defines a contract between ejb-jar file producers and consumers.
Deployment descriptor file uses XML syntax.
The structural declarations are given with enterprise-bean element.