code: public String queryParameter(String name) {
          if (queryNamesAndValues == null) return null;
          for (int i = 0, size = queryNamesAndValues.size(); i < size; i += 2) {
              if (name.equals(queryNamesAndValues.get(i))) {
                  return queryNamesAndValues.get(i + 1);
              }
          }
          return null;
      }
docs: Returns the first query parameter named {@code name} decoded using UTF-8, or null if there is
  no such query parameter.
  
  <p><table summary="">
  <tr><th>URL</th><th>{@code queryParameter("a")}</th></tr>
  <tr><td>{@code http://host/}</td><td>null</td></tr>
  <tr><td>{@code http://host/?}</td><td>null</td></tr>
  <tr><td>{@code http://host/?a=apple&k=key+lime}</td><td>{@code "apple"}</td></tr>
  <tr><td>{@code http://host/?a=apple&a=apricot}</td><td>{@code "apple"}</td></tr>
  <tr><td>{@code http://host/?a=apple&b}</td><td>{@code "apple"}</td></tr>
  </table>