private static @Nullable String findCaseToggleableChild(File dir) {
    try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir.toPath())) {
      for (Path path : stream) {
        String name = path.getFileName().toString();
        if (!name.toLowerCase(Locale.getDefault()).equals(name.toUpperCase(Locale.getDefault()))) {
          return name;
        }
      }
    }
    catch (Exception ignored) { }
    return null;
  }
private static @Nullable String findCaseToggleableChild(File dir)