Java Given a non-empty array of integers, each element appears twice except one that appears only once. Find the element that appears only once.

Given a non-empty array of integers, each element appears twice except one that appears only once. Find the element that appears only once. 
Example 1: 
Input: [2,2,1] 
Output: 1 

Example 2: 
Input: [4,1,2,1,2] 
Output: 4

public class Test37 {
    public static void main(String[] args) {
        int[] arr={2,2,1};
        int[] arr2={4,1,2,1,2};
        findTwe(arr);
        System.out.println();
        findTwe(arr2);

    }

    private static void findTwe(int[] arr) {
        for (int i = 0; i < arr.length; i++) {
            int tmp=0;
            for (int j = 0; j < arr.length; j++) {
                if(arr[i]==arr[j]){
                    tmp++;
                }
            }
            if(tmp==1){
                System.out.println(arr[i]);
            }
        }
    }

}

Achieving the result: