title: Why "extends" precedes "implements" in class declaration
body: <p>Why must <code>implement</code> always be written after <code>extend</code> in a class declaration? For example: </p>
  
  <pre><code>public class Register extends ActionSupport implements ModelDriven
  </code></pre>
  
  <p>Why can it not be:</p>
  
  <pre><code>public class Register implements ModelDriven extends ActionSupport 
  </code></pre>
  
  <p>The latter produces a compile-time error.</p>