* @param s1
     *            The first element of the class name
     * @param s2
     *            The second element of the class name
     * @return The concatenated name
     */
    public static String concatName(final String s1, final String s2) {
        if (StringUtil.isEmpty(s1) && StringUtil.isEmpty(s2)) {
            return null;
        }
        if (!StringUtil.isEmpty(s1) && StringUtil.isEmpty(s2)) {

        }

        @Override
        public boolean isExistClass(final String className) {
            final File file = new File(baseDir, toClassFile(ClassUtil.concatName(rootPackage, className)));
            return file.exists();
        }

        @Override
        public void forEach(final ClassHandler handler) {