* filesystem due to NTFS's <a href="https://goo.gl/vTpJi4">Alternate Data Streams</a>.
   *
   * @since 11.0
   */
  public static String getFileExtension(String fullName) {
    checkNotNull(fullName);
    String fileName = new File(fullName).getName();
    int dotIndex = fileName.lastIndexOf('.');
    return (dotIndex == -1) ? "" : fileName.substring(dotIndex + 1);
  }

  /**

   * filesystem due to NTFS's <a href="https://goo.gl/vTpJi4">Alternate Data Streams</a>.
   *
   * @since 11.0
   */
  public static String getFileExtension(String fullName) {
    checkNotNull(fullName);
    String fileName = new File(fullName).getName();
    int dotIndex = fileName.lastIndexOf('.');
    return (dotIndex == -1) ? "" : fileName.substring(dotIndex + 1);
  }

  /**