Потокобезопасная реализация метода в репозитории

public class Meal {
    private int id;
    private LocalDateTime dateTime;
    private String description;
    private int calories;
 
    public Meal(LocalDateTime dateTime, String description, int calories) {
        this.dateTime = dateTime;
        this.description = description;
        this.calories = calories;
    }
 
    public int getId() {
        return id;
    }
 
    public void setId(int id) {
        this.id = id;
    }
...

...
    private AtomicInteger mealAtomicId = new AtomicInteger(0);
 
    @Override
    public void create(Meal meal) {
            meal.setId(mealAtomicId.incrementAndGet());
            MealDb.getMealMap().put(meal.getId(), meal);
    }
...

@Override
public void create(Meal meal) {     // 2 треда вызывают данный метод с одним meal
    final var id = mealAtomicId.incrementAndGet();  // thread1: id == 1, thread2: id == 2
    meal.setId(id);     // meal.id == 1 or meal.id == 2 (???)
    final var mealMap = MealDb.getMealMap();    // Дальше можно не продолжать...
    final var newId = meal.getId();
    mealMap.put(newId, meal);
}

@Override
    public Meal create(Meal meal) {
        if (meal.isNew()) {
            meal.setId(mealAtomicId.incrementAndGet());
            MealDb.getMealMap().put(meal.getId(), meal);
            return meal;
    }
        }
        return MealDb.getMealMap().computeIfPresent(meal.getId(), (id, oldMeal) -> meal);
    }

getMealMap().computeIfPresent(meal.getId(), (id, oldMeal) -> meal);

getMealMap().putIfAbsent(meal.getId(), meal);

@Override
public void create(Meal meal) {
    synchronized(meal) {
        meal.setId(mealAtomicId.incrementAndGet());
        MealDb.getMealMap().put(meal.getId(), meal);
    }
}

public class Bad {
 
    private static final int INVALID_ID = -42;
 
    public static void main(String[] args) {
        int i = 0;
        try {
            for (; i < 100_000; i++) {
                test();
            }
        } catch (Exception e) {
            System.err.printf("ERROR at iteration #%d: %s%n", i, e);
        }
    }
 
    private static void test() throws InterruptedException {
        final var meal = new Meal();
        meal.setName("Breakfast");
        meal.setPrice(12_00);
 
        final var db = new MealDb();
        final var pool = Executors.newFixedThreadPool(2);
        pool.submit(() -> meal.setId(INVALID_ID));
        pool.submit(() -> db.create(meal));
        pool.shutdown();
        if (!pool.awaitTermination(2, TimeUnit.SECONDS)) {
            throw new RuntimeException("failed to terminate thread pool");
        }
 
        if (meal.getId() == INVALID_ID) {
            throw new IllegalStateException("oh no! invalid meal id! Expected: " + db.lastId() + ", got: " + INVALID_ID);
        }
    }
}