带有2个数组列表的Java toString

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> list1 = new ArrayList<>();
        list1.add(1);
        list1.add(2);
        list1.add(3);

        ArrayList<String> list2 = new ArrayList<>();
        list2.add("A");
        list2.add("B");
        list2.add("C");

        System.out.println("list1: " + list1.toString());
        System.out.println("list2: " + list2.toString());
    }
}

list1: [1, 2, 3]
list2: [A, B, C]