Python web service for a java application?
When developing in a framework, it is generally simpler to develop with the language of the framework than it is to develop with a different language.
Servlets are components of the web server (which is also called a Servlet container).  The Servlet container and the required Servlet API is all Java.  While you could Frankenstein in some sort of Python code, odds are good that the integration effort would eventually make that "simplicity" far more complex than you particularly desire.
If you want a Python web application, use a Python web framework.  If you want a Java web application, use a Java framework.  Don't try to make the two cross compatible, as the integration points (and used / offered conveniences) are not even guaranteed to be present on the "other side" of the fence.
Forgive me if this is a stupid question. I am completely new to building web services and complete web apps. 
I want to develop a particular functionality for a java based web application. However this functionality is simpler to develop with Python. So is it possible If i develop this web service with Python and use it for a Java based webapp?