code: public static URL addQueryParameter(URL url, String name, String value)
    {
      URLBuilder ub = createFromURL(url);
      ub.addQueryParameter(name, value);
      return ub;
    }
docs: Convenient call which adds a query parameter to the give url.
  
  @param url the original URL: will stay unchanged
  @param name the name of the query parameter
  @param value the value of the query parameter
  @return the new URL