How to map the welcome file to a servlet?

In a Java web application, assume you have a project structure like this:

Now we only have one simple servlet. This application will be deployed to context-root "atam". So when I type localhost:8080/atam I want the AtamServlet to take control. Here is how you can do it, in web.xml make sure you have this:
Now, the initial request will go to /atam/index which will be handled by AtamServlet...