In this example, the Bean Provider has chosen to package the enterprise bean client view classes in a separate jar file and to reference that jar file from the other jar files that need those classes.
Those classes are needed both by ejb2.jar, packaged in the same application as ejb1.jar, and by ejb3.jar, packaged in a different application.
Those classes are also needed by ejb1.jar itself because they define the remote interface of the enterprise beans in ejb1.jar, and the Bean Provider has chosen the by reference approach to making these classes available.
The deployment descriptor for ejb1.jar names the client view jar file in the ejb-client-jar element. Because ejb2.jar requires these client view classes, it includes a Class-Path reference to ejb1_client.jar.
The Class-Path mechanism must be used by components in app2.ear to reference the client view jar file that corresponds to the enterprise beans packaged in ejb1.jar of app1.ear.
Those enterprise beans are referenced by enterprise beans in ejb3.jar. Note that the client view jar file must be included directly in the app2.ear file.