JSR 109 and JSR 921 (Implementing Enterprise Web Services) define the programming model and run-time architecture to deploy and look up Web services in the J2EE environment; more specifically, in the Web, EJB, and Client Application containers. One of its main goals is to ensure vendors' implementations interoperate.
JSR 109 and JSR 921 build on top of JAX-RPC to cover the use of JAX-RPC in a J2EE environment, as well as the implementation and deployment of Web services to a J2EE application server. JSR 109 and JSR 921 define a set of XML-based deployment descriptors to standardize Web services and Web service client deployments in the J2EE environment. These tools support JSR 109 for J2EE 1.3 and JSR 921 for J2EE 1.4.
For more information, refer to: JSR 109, "Implementing Enterprise Web Services and JSR 921: Implementing Enterprise Web Services 1.1.