code: public static String decode(String encoded) {
          try {
              return URLDecoder.decode(encoded, "UTF-8");
          } catch (UnsupportedEncodingException e) {
              throw new EsHadoopIllegalArgumentException("Cannot decode string [" + encoded + "]", e);
          }
      }
docs: Decodes a "application/x-www-form-urlencoded" format string back to a regular string value,
  returning the "%XX" codes back into UTF-8 Characters.
  @param encoded String in "application/x-www-form-urlencoded" format.
  @return A UTF-8 formatted String.