docs: public static String[] splitFileNameIntoPreSuffix(String fileName) {
          String[] preSuffix = {fileName, EMPTY};
          int dotIndex = fileName.lastIndexOf(DOT);
          if (dotIndex > 0) {
              preSuffix[0] = fileName.substring(0, dotIndex);
              preSuffix[1] = fileName.substring(dotIndex);
          }
          return preSuffix;
      }