docs: static String getDataSourceClassName(Collection<String> fileNames) {
  
          for (Map.Entry<String, String[]> entry : classNamesByKey.entrySet())
              if (contains(fileNames, entry.getKey())) {
                  String[] classNames = entry.getValue();
                  return classNames == null ? null : classNames[0];
              }
  
          return null;
      }