Add One To Number

public class Solution {
    public int[] plusOne(int[] A) {
        ArrayList<Integer> al = new ArrayList<>();
        //add 1 to last of element 
        int sum = (A[A.length-1]+1)%10; 
        int carry = (A[A.length-1]+1)/10;
        al.add(sum);
        //loop from second last to first
        for(int i=A.length-2;i>=0;i--){
            int num = A[i]+carry;
            sum = num%10;
            carry = num/10;
            al.add(sum);
        }
        if(carry != 0){ //it has no starting zeros
            al.add(carry);
        } else { //removing zeros
            while(al.get(al.size()-1) == 0 ){
                al.remove(al.size()-1);
            }
        }
        //generate response
        int res[] = new int[al.size()];
        for(int i=0;i<res.length;i++){
            res[i] = al.get(res.length-i-1);
        }
        return res;
    }
}