LeetCode 448 --- Find All Numbers Disappeared in an Array

public class Problem448 {

    public static void main(String[] args) {
        int [] a={4,3,2,7,8,2,3,1};
        // TODO Auto-generated method stub
        findDisappearedNumbers(a);
    }
    public static List<Integer> findDisappearedNumbers(int[] nums) {
        List<Integer> list =new ArrayList<Integer>();
        for(int i=1;i<=nums.length;i++)
            list.add(i);
        for(int i=0;i<nums.length;i++)
            list.remove(new Integer(nums[i]));
        return list;

    }

}