title: what is java:comp/env?
body: <p>what is meant by <code>java:comp/env</code> ? </p>
  
  <p>What does the look up like :</p>
  
  <pre><code>Context envContext = (Context)initContext.lookup("java:comp/env");
  </code></pre>
  
  <p>do ?</p>
  
  <p>I understand that a look-up like :</p>
  
  <pre><code>(DataSource)envContext.lookup("jdbc/MyDatasource")
  </code></pre>
  
  <p>looks up for the name <code>MyDatasource</code> in the <code>context.xml</code> or <code>web.xml</code> to get the URL of the database. <em>Is it so ? !!</em> But what does the former look up do ?</p>