The Java API for XML-based RPC (JAX-RPC) specification enables Java language developers to develop SOAP-based interoperable and portable Web services. JAX-RPC provides core APIs for developing and deploying Web services on a Java platform and is a required part of the J2EE 1.4 platform. JAX-RPC Web services can also be developed and deployed on J2EE 1.3 containers.
WebSphere Application Server Versions 5.0.2, 5.1 and 5.1.1 supports JAX-RPC 1.0.
The JAX-RPC standard covers the programming model and bindings for using Web Services Description Language (WSDL) for Web services in the Java language.
JAX-RPC defines the mappings between the WSDL port types and the Java interfaces, as well as between Java language and eXtensible Markup Language (XML) schema types.
Review the Javadoc for a complete list of API's. You can also review several articles about the development of Web services at Web services: Resources for learning.