title: Force a class to override the .equals method
body: <p>I have a bunch of class who implement a common interface : Command. </p>
  
  <p>And this bunch of class goes to a Map.</p>
  
  <p>To get the Map working correctly, I need to each class who implements Command to override the <code>Object.equals(Object other)</code> method.</p>
  
  <p>it's fine.</p>
  
  <p>But i whould like to force the overriding of equals. => Have a compilation error when something who implement command dont override equals.</p>
  
  <p>It's that possible ?</p>
  
  <p>Edit : BTW , i will also need to forcing the override of hashcode...</p>