code: Map<String, String> parseQueryString(final String queryString, final Map<String, String> into) {
      final Map<String, String> result = (into == null) ? new HashMap<>() : into;
  
      if (StringUtils.isNotEmpty(queryString)) {
        for (final String keyValuePair : queryString.split("&")) {
          final String[] keyValue = keyValuePair.split("=", 2);
          if (keyValue.length > 1) {
            result.put(keyValue[0], urlUtils.decodeQueryString(keyValue[1]));
          } else {
            result.put(keyValue[0], StringUtils.EMPTY);
          }
        }
      }
  
      return result;
    }
docs: Parse the given query-string and store all parameters into a map.
  
  @param queryString The query-string.
  @param into The map to use. If the given map is <code>null</code> a new map will be created.
  @return A map containing all keys value pairs of the query-string.