LeetCode 389. Find the Difference

public class Solution {    public char findTheDifference(String s, String t) {        char[] sToChars = s.toCharArray();        char[] tToChars = t.toCharArray();        char r = '\0';        for (int i = 0; i < sToChars.length; i++) r = (char)(r ^ sToChars[i]);        for (int i = 0; i < tToChars.length; i++) r = (char)(r ^ tToChars[i]);        return r;    }}