public static void main(String[] args) throws IOException {
        File dir = new File("c/exam/haha");
        if (dir.exists() && dir.isDirectory()) {
            System.out.println("The directory already exits!".toUpperCase());
        } else {
            if (dir.mkdirs()) {
                System.out.println("the directory has been created!".toUpperCase());
                File f = new File(dir, "test.txt");
                f.createNewFile();
                f.setReadOnly();
                System.out.println("end of creation".toUpperCase());
            } else {
                System.out.println("failed!".toUpperCase());
            }
        }
    }