Before you start on web services make sure you are well grounded in plain old HTTP servlets.
Next - very important - consider the requirements of the web service in this new project, aiming at a decision between RESTful style and SOAP. Especially consider the security requirements.
If it can be done as a RESTful architecture, it will be simpler and faster to get something going than if you have to dig into SOAP.
Whichever way you go, there are toolkits which come with rather complete examples of both server and client side code. Get those examples running before you try to get your custom service working. Hopefully your boss will realize that time spent on getting examples running will be faster in the long run.