Axis is a framework to help you to develop Web Services. It includes a JAX-RPC implementation. Except that it has a lot of other stuffs. The SUN JAX-RPC library is another implementation. Apache has beening working on Web Services for a long time. A lot of developers have used the Axis or its ancestors to develop their web services. Sun added the JAX-RPC into J2EE1.4 Most of the servers are J2EE1.3 compatible. There is no SUN JAX-RPC available.