code: public void l7dlog(Priority priority, String key, Throwable t) {
          if (repository.isDisabled(priority.level)) {
              return;
          }
          if (priority.isGreaterOrEqual(this.getEffectiveLevel())) {
              String msg = getResourceBundleString(key);
              // if message corresponding to 'key' could not be found in the
              // resource bundle, then default to 'key'.
              if (msg == null) {
                  msg = key;
              }
              forcedLog(FQCN, priority, msg, t);
          }
      }
docs: Log a localized message. The user supplied parameter <code>key</code> is replaced by its localized version from the resource bundle.
  
  @see #setResourceBundle
  @since 0.8.4