What are Java Web Services ( Introduction to Web Services )
Java Web Services are a set of programming interfaces , located somewhere on the internet and that can be accessible from different software applications or different platforms using XML based messages through internet based protocols (Ex : HTTP).
From the above diagram,even though all the clients may not have the same platform but they can able to access the services from the service provider by using internet protocols.
Types of Java Web Services :
Big (SOAP) Web Services :It uses SOAP (Simple Object Access Protocol) to exchange XML messages between client and server.The WSDL(Web Service Description Language) file plays a major role and it can be used to describe the details of the contract, which may include messages, operations, bindings, and the location of the web service.
RESTful Web Services :It uses existing well-known W3C and IETF (Internet Engineering Task Force) standards (like HTTP, XML, URI, MIME) and have a lightweight infrastructure that allows services to be built with minimal tooling. Developing RESTful services is inexpensive and thus has a very low barrier for adoption.
Advantages of Java Web Services :
Platform independent.So it can be available in nearly all platforms.
Web services can be combined in a loosely coupled way to achieve complex operations and good to reuse.
The integration cost is less and the integration speed is high.
These are using Common and standard network protocols like HTTP,SMTP etc.