title: log4j logging hierarchy order
body: <p>What is the hierarchy of log4j logging?</p>
  
  <pre><code>DEBUG
  INFO
  WARN
  ERROR
  FATAL
  </code></pre>
  
  <p>Which one provides the highest logging which would be helpful to troubleshoot issues?
  Can any one provide the order or hierarchy in which logging take place from highest to lowest?
  Thanks!</p>