Find single number in array Java

TestSigleNumberInArray.java

import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

class TestSigleNumberInArray {
    public static void main(String[] args) {
        System.out.println("Start generation");
        var lotsOfIntegers = IntStream.rangeClosed(1, 12312300)
            .boxed()
            .collect(Collectors.toList());
        var integersTest = List.of(4, 6, 4, 3, 5, 3, 5);
        var integers = new ArrayList<Integer>();

        System.out.println("Start joining");
        integers.addAll(lotsOfIntegers);
        integers.addAll(integersTest);
        integers.addAll(lotsOfIntegers);

        long startTime = System.nanoTime();
        System.out.println("Start finding");
        var nonPairedInt = findNonPairedIntXor(integers);
        long endTime = System.nanoTime();

        long executionTime = (endTime - startTime) / 1_000_000;
        System.out.println("Time Taken: " + executionTime + "ms. " + "Result: " + nonPairedInt);
    }

    private static int findNonPairedIntHashMapStatistic(List<Integer> integers) {
        return integers.stream()
            .collect(Collectors.toMap((el) -> el, el -> 1, Integer::sum))
            .entrySet()
            .stream()
            .filter(entry -> entry.getValue() % 2 == 1)
            .findAny()
            .map(Map.Entry::getKey)
            .orElseThrow();
    }

    private static int findNonPairedIntHashSetPresence(List<Integer> integers) {
        var store = new HashSet<Integer>();

        for (Integer integer : integers) {
            if (store.contains(integer)) {
                store.remove(integer);
            } else {
                store.add(integer);
            }
        }

        return store.iterator().next();
    }

    private static int findNonPairedIntXor(List<Integer> integers) {
        var xorRes = 0;

        for (Integer integer : integers) {
            xorRes ^= integer;
        }

        return xorRes;
    }
}