public static void main(String[] args) {
        int[] aa = {1,2,2,3,4,1,5};
        returnMost(aa);
    }
    public static int returnMost(int[] arr){
        if (arr == null || arr.length == 0)
            return 0;
        int Max= 0;
        int result = 0;
        HashMap<Integer,Integer> map = new HashMap<>();
        for (int i : arr) {
            map.merge(i, 1, Integer::sum);
            if (map.get(i) >= Max) {
                Max = map.get(i);
                result = i;
            }
        }
        return result;

    }