title: Should logger be private static or not
body: <p>Should logger be declared static or not? Usually I've seen two types of declaration for a logger :</p>
  
  <pre>
      protected Log log = new Log4JLogger(aClass.class);
  </pre>
  
  <p>or</p>
  
  <pre>
      private static Log log = new Log4JLogger(aClass.class);
  </pre>
  
  <p>Which one should be used? what are the pro's and con's of both?</p>