JSR 109 (Implementing Enterprise Web Services) defines the programming model and run-time architecture to deploy and look up Web services in the Java EE environment; more specifically, in the Web, EJB, and Client Application containers. One of its main goals is to ensure vendors' implementations interoperate.
JSR 109 builds on top of JAX-RPC to cover the use of JAX-RPC in a Java EE environment, as well as the implementation and deployment of Web services to a Java EE application server. JSR 109 defines a set of XML-based deployment descriptors to standardize Web services and Web service client deployments in the Java EE environment. JSR 921 was a maintenance revision of JSR 109, and has since been replaced by the updated version of JSR 109.
For more information, refer to: JSR 109, "Implementing Enterprise Web Services and JSR 921: Implementing Enterprise Web Services 1.1.