docs: @Override
      protected ModelMetadataKey getModelMetadataKey(String keyName){
          ModelMetadataKey key = getMetadataKeyCache().get(keyName);
          if (key == null) {
              getMetadataKeyCache().putIfAbsent(keyName, super.getModelMetadataKey(keyName));
              key = getMetadataKeyCache().get(keyName);
          }
          return key;
      }