code: public void addHandler(Handler handler) throws SecurityException {
          // Check for null handler
          handler.getClass();
          checkPermission();
          handlers.add(handler);
      }
docs: Add a log Handler to receive logging messages.
  <p>
  By default, Loggers also send their output to their parent logger.
  Typically the root Logger is configured with a set of Handlers
  that essentially act as default handlers for all loggers.
  
  @param   handler a logging Handler
  @exception  SecurityException  if a security manager exists and if
  the caller does not have LoggingPermission("control").