code: public static String formURLDecode(String string) {
          Preconditions.checkNotNull(string, "Cannot decode null string");
  
          try {
              return URLDecoder.decode(string, UTF_8);
          } catch (UnsupportedEncodingException uee) {
              throw new IllegalStateException(ERROR_MSG, uee);
          }
      }
docs: Decodes a application/x-www-form-urlencoded string
  
  @param string form-urlencoded string
  @return plain string