With the optional classpath element, you specify the classpath for other resources (classes and JARs) that the application can use. These are not necessarily available when the application is being deployed but an exception will occur if they are not available at runtime.
For the DTD, see application-j2ee-engine.dtd.
You have opened the application-j2ee-engine.xml file in the multipage editor.
1. Choose the Expert Settings tab.
2. In the Additional classpath field, enter the relevant classpath.
The classpath can be absolute or relative to the root of the server.