class ExpansibleURLClassLoader extends URLClassLoader {

    public void addUrl(final URL url) {
        URL[] urls = getURLs();
        if (Arrays.asList(urls).contains(url)) {
            return;
        }
        addURL(url);
    }

    public  ExpansibleURLClassLoader(final URL[] urls);
    public  ExpansibleURLClassLoader(final URL[] urls, final ClassLoader parent);

}