Shredded online written test & interview, java do not know in advance the length of the array, how input array

public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入数组");
		ArrayList<Integer> list = new ArrayList<>();
		while(sc.hasNext()) {
			int num = sc.nextInt();
			if(num == -99999) {
				break;
			}
			list.add(num);
		}
		
		int[] arr = new int[list.size()];
		for (int i = 0; i < arr.length; i++) {
			arr[i] = list.get(i);
		}
	}

Of course, the value of -99999 is only one never to appear.