public URL(String spec) throws MalformedURLException { this((URL) null, spec, (URLStreamHandler) null);
public URL(String protocol, String host, int port, String file) throws MalformedURLException { this(protocol, host, port, file, null);
    public URL(String spec) throws MalformedURLException {        this((URL) null, spec, (URLStreamHandler) null);    }