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:
<servlet>
    <servlet-name>AtamServlet</servlet-name>
    <servlet-class>com.tugay.atam.AtamServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>AtamServlet</servlet-name>
    <url-pattern>/index</url-pattern>
</servlet-mapping>
<welcome-file-list>
    <welcome-file>index</welcome-file>
</welcome-file-list>
Now, the initial request will go to /atam/index which will be handled by AtamServlet...