Servlet JSP web.xml

I see a feature in NetBeans for selecting a JSP for a Servlet and the result XML in web.xml is like this:

<servlet>
    <servlet-name>TestServlet</servlet-name>
    <jsp-file>/index.jsp</jsp-file>
</servlet>

What does it mean? And what is it for? Is it like code behind architecture in ASP .NET?