code: @Nonnull
      public String getLoggerEffectiveLevel(@Nullable String loggerName) {
          try {
              loggerName = loggerName == null ? "" : loggerName;
  
              if (loggerName.isEmpty()) {
                  return LogManager.getRootLogger().getLevel().toString();
              }
  
              while (true) {
                  Logger logger = LogManager.exists(loggerName);
                  if (logger == null || logger.getLevel() == null) {
                      int idx = loggerName.lastIndexOf('.');
                      if (idx > 0) {
                          loggerName = loggerName.substring(0, idx - 1);
                      } else {
                          return LogManager.getRootLogger().getLevel().toString();
                      }
                  } else {
                      return logger.getLevel().toString();
                  }
              }
          } catch (RuntimeException e) {
              logger.warn("Exception getting effective logger level " + loggerName, e);
              throw e;
          }
      }
docs: Get the logger level that applies to the given logger name.
  
  @param loggerName logger name
  @return effective logger level, never <code>null</code>