code: public synchronized void setLevel(Level newLevel) throws SecurityException {
          if (newLevel == null) {
              throw new NullPointerException();
          }
          checkPermission();
          logLevel = newLevel;
      }
docs: Set the log level specifying which message levels will be
  logged by this <tt>Handler</tt>.  Message levels lower than this
  value will be discarded.
  <p>
  The intention is to allow developers to turn on voluminous
  logging, but to limit the messages that are sent to certain
  <tt>Handlers</tt>.
  
  @param newLevel   the new value for the log level
  @exception  SecurityException  if a security manager exists and if
  the caller does not have <tt>LoggingPermission("control")</tt>.