Web Service Description Language (WSDL) represents an IDL describing the
contract between the service requestor and the service provider in much the
same way that a Java interface represents a contract between client code and
an actual Java object. The crucial difference is that WSDL is platform- and
language-independent and used primarily (although not exclusively) to
describe SOAP services.
The WSDL 1.1 specification has been accepted at the World Wide Web Consortium
(W3C) and is the predominant version for describing Web Services today. At
W3C, work on the next generation of WSDL, i.e., version 2.0, has been under
way for some time now. WSDL 2.0 promises to describe not only traditional
SOAP Web Services, but also a wide variety of services provided over any
network. W3C has published the Candidate Recommendation for WSDL 2.0. WSDL
2.0 is substantially different... (more)