如何使用Java检查一个数字是否在列表中(没有给定的参数)

import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Integer> numbers = new ArrayList<>();
        numbers.add(1);
        numbers.add(2);
        numbers.add(3);
        numbers.add(4);
        numbers.add(5);

        int targetNumber = 3;

        if (numbers.contains(targetNumber)) {
            System.out.println(targetNumber + " is in the list.");
        } else {
            System.out.println(targetNumber + " is not in the list.");
        }
    }
}