*
     * @param url
     *            The resource URL. Must not be {@literal null}.
     * @return The external form.
     */
    public static String toExternalForm(final URL url) {
        assertArgumentNotNull("url", url);

        final String s = url.toExternalForm();
        return URLUtil.decode(s, "UTF8");
    }

    /**
     * Returns the file name of the resource.
     *
     * @param url

        final URL url = ResourceUtil.getResource(toClassFile(referenceClass.getName()));
        final String[] path = referenceClass.getName().split("\\.");
        String baseUrl = url.toExternalForm();
        for (final String element : path) {
            final int pos = baseUrl.lastIndexOf('/');
            baseUrl = baseUrl.substring(0, pos);
        }