携程第二道编程，java无法判断输入结束

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        List<Integer> list = new ArrayList();
        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            public void run() {
                int n = (int) Math.sqrt(list.size());
                int[][] matrix = new int[n][n];
                for (int i = 0; i < list.size(); i++) {
                    matrix[i / n][i % n] = list.get(i);
                }
                new Main().new Rotate_Image().rotate(matrix);
                for (int i = 0; i < n; i++) {
                    for (int j = 0; j < n; j++) {
                        System.out.print(matrix[i][j] + " ");
                    }
                    System.out.println();
                }
                System.exit(0);
            }
        }, 2000);
        while (in.hasNextInt()) {
            list.add(in.nextInt());
        }
    }