title: relation between log4j and apache.commons.logging
body: <p>Could anybody please tell me 
  what's the relation between log4j and apache.commons.logging ? which one is more popular and better ?</p>
  
  <p>I have imported an existing Application in which they have imported <code>import org.apache.commons.logging.LogFactory;</code> and written a separate class called <code>Log</code> and overridden some of the methods as <code>critical</code>, <code>warn</code>, <code>info</code> </p>
  
  <p>For instance </p>
  
  <pre><code> public static void info(String caller, String toWrite)
     {
        write(caller,toWrite,Log.INFO);
     }
  </code></pre>
  
  <p>Could anybody please tell me is log4j and  apache.commons.logging are different ??</p>