The JAX-RPC deployment descriptor, webservices.xml, provides metadata (such as names and descriptions of the SEIs, service beans, and WSDL documents) about all of the Web Services in a given Web application.

The mapping file defines the association between a WSDL file and an SEI and implementation class, by mapping namespaces to Java packages. This mapping is used when serializing and deserializing XML files. There is a separate JAX-RPC mapping file for each Web Service, and the name of each file reflects the method the service is based on. For example, if the method is getOrderStatus, the mapping file for the Web Services is named getOrderStatusMapping.xml.