LeetCode: Single Number

Given an array of integers, every element appears twice except for one. Find that single one.
Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Solution:

public class Solution {
    public int singleNumber(int[] A) {
        int temp = A[0];
        for(int i=1; i<A.length; i++)
            temp^=A[i];
        return temp;
    }
}