code: public boolean addLogger(Logger logger) {
          final String name = logger.getName();
          if (name == null) {
              throw new NullPointerException();
          }
          drainLoggerRefQueueBounded();
          LoggerContext cx = getUserContext();
          if (cx.addLocalLogger(logger, this)) {
              // Do we have a per logger handler too?
              // Note: this will add a 200ms penalty
              loadLoggerHandlers(logger, name, name + ".handlers");
              return true;
          } else {
              return false;
          }
      }
docs: Add a named logger.  This does nothing and returns false if a logger
  with the same name is already registered.
  <p>
  The Logger factory methods call this method to register each
  newly created Logger.
  <p>
  The application should retain its own reference to the Logger
  object to avoid it being garbage collected.  The LogManager
  may only retain a weak reference.
  
  @param   logger the new logger.
  @return  true if the argument logger was registered successfully,
  false if a logger of that name already exists.
  @exception NullPointerException if the logger name is null.