XML-based remote calls are a key Web services technology. The Java API for XML-based RPC (JAX-RPC) 2.0 is the second-generation XML-based RPC Java standard. Currently in early draft review in the JCP as JSR 224, JAX-RPC 2.0 promises to vastly simplify RPC-based Web service development. Part of that ease results from new JDK 1.5 features, such as annotations and the concurrency API. This article reviews key JAX-RPC 2.0 features, and highlights how taking advantage of recent additions to Java make JAX-RPC 2.0 a more flexible API.