title: java mandatory package declaration
body: <p>In java, why is it mandatory for each class to declare the package it belongs to. I mean, package hierachy is already described/enforced using the folder
  structure of the file system. It looks to me that the line:</p>
  
  <pre><code>package com.mypackage;
  </code></pre>
  
  <p>As the first line of each class is somehow a redundant information. But I'm pretty sure there's a good reason for it to be there.</p>