code: protected static Log getLogger() {
          Log l = logger;
          if (l == null) {
              l = LogFactory.getLog(LOGGER_NAME);
              logger = l;
          }
          return l;
      }
docs: Inits and/or returns already initialized logger. <br>
  You have to use this method in order to use the logger,<br>
  you should not call the private variable directly.<br>
  This was done because Tomcat may instantiate all listeners before calling contextInitialized
  on any listener.<br>
  Note that there is no synchronization here on purpose. The object returned by getLog for a
  logger name is<br>
  idempotent and getLog itself is thread safe. Eventually all <br>
  threads will see an instance level logger variable and calls to getLog will stop.
  
  @return the log for this class