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?

public static int singleNumber1(int nums[]) {if (nums == null) return 0;int length = nums.length;int count = 0;for (int i = 0; i < length ; i++) {for (int j = 0; j < length; j++) {if (i != j) {if (nums[i] == nums[j]) continue;else {count++;  }}}if (count == length - 1)return nums[i];count = 0;}		return 0;