title: What do ContextLoaderListener and RequestContextListener do?
body: <p>I have an application, where i am using Spring.
  And in my web.xml i use lines below </p>
  
  <pre><code>&lt;web-app&gt;
       ....
       &lt;listener&gt;
            &lt;listener-class&gt;
               org.springframework.web.context.ContextLoaderListener
            &lt;/listener-class&gt;
         &lt;/listener&gt;
         &lt;listener&gt;
            &lt;listener-class&gt;
               org.springframework.web.context.request.RequestContextListener
            &lt;/listener-class&gt;
         &lt;/listener&gt;
         ....
  &lt;/web-app&gt;
  </code></pre>
  
  <p>What are they ?
  Are they mandatory ?</p>