title: log4cxx config file syntax
body: <p>I'm just discovering log4cxx logging framework.
  It seems there are two different syntaxes for writing config file:</p>
  
  <ol>
  <li><p>xml manner</p></li>
  <li><p>key-value manner</p></li>
  </ol>
  
  <p>Is there a difference or a best practice in this two approaches?</p>