{
        if (urlConnection == null)
        {
          urlConnection = url.openConnection();
          if (urlConnection instanceof HttpURLConnection)
          {
            HttpURLConnection httpURLConnection = (HttpURLConnection)urlConnection;
            httpURLConnection.setRequestMethod("HEAD");
            httpURLConnection.getResponseCode();
          }
        }
        if (urlConnection.getHeaderField("last-modified") != null)
        {
          result.put(URIConverter.ATTRIBUTE_TIME_STAMP, urlConnection.getLastModified());
        }
      }