code: public static String getParentLoggerName(String loggerName) {
  
          int dotIndex = loggerName.lastIndexOf(".");
          if (dotIndex < 0) {
              return null;
          } else {
              return loggerName.substring(0, dotIndex);
          }
  
      }
docs: Gets the parent logger name for a given logger name, or null if there is no parent logger name.<p>
  
  @param loggerName the name of a logger
  @return the parent name of the logger, or null if the logger name has no parent