Deployment descriptors are xml files containing deployment information, such as the settings you specify in the Interface Mapping Toolkit. Java application servers require deployment descriptors for the archive files (.jar, .war and .ear) to be deployed. At run time, the Java application server reads the descriptors and acts accordingly. Deployment descriptors are not required for the generated Java beans.
When you generate an EJB or client, the following generic deployment descriptors are created and packaged into the relevant archive files:
Some Java application servers require additional deployment descriptors in the archive files. These descriptors are generated automatically for the supported application servers.
If your application server requires additional deployment descriptors and these are not generated, you need to create them manually and add them to the archive files.