Do Java programmers really need SOAP?. Why is adopting SOAP in Java premature?
First, a simple form of Web services can already be implemented with Java Servlets. A Servlet can receive an HTTP POST with an XML document as the content and return an XML document as the response. Thus we could define a simple Web service as:
Web service = (XML input document, service name, XML output document)
Given the strong data typing of the XML schema, this simpler model can serve any purpose that SOAP RPC currently serves. If a simpler alternative exists, such as a model where the input is a single XML message and the output is a single XML message, then why use an XML instantiation of legacy RPC implementations.