Spring-WS provides a powerful message dispatching framework, a WS-Security solution that integrates with your existing application security solution, and a Client-side API that follows the familiar Spring template pattern.
It specifies the location of the service and the operations (or methods) the service exposes.
For more information about WSDL, refer to the WSDL specification.
For one, you cannot use an XML validator to validate this structure.
Another issue is that the standard way to use these references in SOAP (RPC/encoded) has been deprecated in favor of document/literal (see WS-I Basic Profile).
Especially when interoperability with other platforms is important, it is often better to send encapsulated XML documents, containing all the data necessary to process the request.
Conceptually, XML-based Web services are better off being compared to message queues rather than remoting solutions.
Spring Web Services focuses on creating these document-driven Web services.
Spring Web Services facilitates contract-first SOAP service development, allowing for the creation of flexible web services using one of the many ways to manipulate XML payloads.
Similar to the field of ORM, where we have an Object/Relational impedance mismatch, there is a similar problem when converting Java objects to XML.