title: Avoid using static access to Exception
body: <p>I've just fired up PHPMD for the first time and, predictably, I've got an error I can't figure out.  The error is</p>
  
  <blockquote>
    <p>Avoid using static access to class 'InvalidArgumentException' in
    method 'setLang'.</p>
  </blockquote>
  
  <p>and the code is</p>
  
  <pre><code>public function setLang($val0) {
      switch ($val0) {
      case ENG:
      case FRE:
      case SPA;
          $this-&gt;lang = $val0;
          break;
      default:
          throw new InvalidArgumentException("Invalid language choice.");
      }
  }
  </code></pre>
  
  <p>I've tried a variety of different things but I think at the end of the day <code>Exception</code> is a static factory (???) so it must have static access.  But, the PHPMD guys are for sure smarter than me so that wouldn't have fazed them.</p>
  
  <p>Why does this warning exist, and how to solve it?</p>