class FileUtils {

    public static String suffix(String filename) {

        String fileSuffix = "";
        if (StringUtils.isNotEmpty(filename)) {
            int lastIndex = filename.lastIndexOf('.');
            if (lastIndex > 0) {
                fileSuffix = filename.substring(lastIndex + 1);
            }
        }
        return fileSuffix;
    }

    private  FileUtils();

}