JAX-WS stands for Java API for XML Web Services. It is a set APIs for creating web services and clients which communicates through XML format. It allows us to write message-oriented (Document-oriented) as well as Remote Procedure Call-oriented (RPC-oriented) web services.
JAX-WS RCP style:
JAX-RPC stands for Java API for XML-based RPC. It allows a Java application to invoke a Java-based Web service with a known description while still being consistent with its WSDL description. JAX-RPC is one of the Java XML programming APIs.
A RPC style SOAP messages body contains an XML representation of the method’s call. It use the method name and its parameters to construct an XML tree which represents the method’s call stack.
JAX-WS Document style:
A Document style SOAP message body contains an XML document that can be validated against a defined XML schema. It is a more customizable and flexible approach as the protocol relies on the pre-defined schema to determine the structure of the SOAP message. That means we are free to customize the SOAP messages as much as we want.