code: protected void collectQueryParameters(HttpRequest request, HttpParameters out) {
  
          String url = request.getRequestUrl();
          int q = url.indexOf('?');
          if (q >= 0) {
              // Combine the URL query string with the other parameters:
              out.putAll(OAuth.decodeForm(url.substring(q + 1)), true);
          }
      }
docs: Collects HTTP GET query string parameters as per OAuth Core 1.0 spec
  section 9.1.1