JAX-WS – is Java API for the XML-Based Web Services – a standard way to develop a Web- Services in SOAP notation (Simple Object Access Protocol).
Calling of the Web Services is performed via remote procedure calls. For the exchange of information between the client and the Web Service is used SOAP protocol. Message exchange between the client and the server performed through XML- based SOAP messages.
Clients of the JAX-WS Web- Service need a WSDL file to generate executable code that the clients can use to call Web- Service.