class FilenameUtils {

    public static boolean isExtension(String filename, String extension) {
        if (filename == null) {
            return false;
        }
        if (extension == null || extension.length() == 0) {
            return (indexOfExtension(filename) == -1);
        }
        String fileExt = getExtension(filename);
        return fileExt.equals(extension);
    }

    public  FilenameUtils();

}