Additional functionalities / abstractions provided by webservice/webservice implementations over servlets/servlet containers?

The whole life cycle and Thread safety of the servlets, servlet context, session handling & http request-response handling are done by servlet containers.

Servlet vs Webservices

Difference between servlet and web service

As mentioned in the answers of the above questions, Webservice is a layer above servlet and webservice implementations uses servlet.

I think the format of the message transported over http is not a factor that will differentiate webservice and servlet. Any http request (even from a program written in c# ) with correct url will be responded by that particular servlet.

c# ex : http://ift.tt/1M3iMgP

So, what are the additional functionalities / abstractions provided by webservice over servlets ?

Thanks in advance :)