title: Extend AND implement in the same class
body: <p>How can I implement an interface AND extend a class to the same class?</p>
  
  <p>This doesn't seem to work (the interface is not implemented at all):</p>
  
  <pre><code>public class StrongChecker extends BasicChecker implements Checker {
  </code></pre>
  
  <p>This doesn't work either (the interface is not implemented at all):</p>
  
  <pre><code>public class StrongChecker extends BasicChecker {
  </code></pre>
  
  <p>And this gives me an error:</p>
  
  <pre><code>public class StrongChecker implements Checker extends BasicChecker {
  </code></pre>
  
  <p>Thanks for your help !</p>