Add Two Numbers

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

Here is my answer, if you have a better solution, please comment below.

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { val = x; } * } */public class Solution {    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {        ListNode head = new ListNode(0);        int add=0;        //int i = 0;        ListNode result = head;        while(l1 != null || l2 != null || add != 0){            int sum = (l1 == null ? 0 : l1.val ) + (l2 == null ? 0 : l2.val) + add;            add = sum / 10;            sum %= 10;            head.next = new ListNode(sum);            head = head.next;             l1 = l1 == null ? null : l1.next ;            l2 = l2 == null ? null : l2.next;        }        return result.next;    }}