29         if (url == null || !url.startsWith(
"/")) 
return url;
    30         if (rootUrl != null) {
    33             UriBuilder builder = UriBuilder.fromPath(url).host(requestUri.getHost());
    34             builder.scheme(requestUri.getScheme());
    35             if (requestUri.getPort() != -1) {
    36                 builder.port(requestUri.getPort());
    38             return builder.build().toString();