title: javadoc doesn't found in my linux machine
body: <p>I'm running on ubuntu 12.04 and when I put in the terminal <code>java -version</code> I got this message:</p>
  
  <pre><code>java version "1.7.0_05"
  Java(TM) SE Runtime Environment (build 1.7.0_05-b05)
  Java HotSpot(TM) 64-Bit Server VM (build 23.1-b03, mixed mode)
  </code></pre>
  
  <p>but despite that, if I put in the terminal <code>javadoc</code> I receive a message as it isn't installed in my machine.</p>