ArrayList

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

public class Main {

    public static void main(String[] args) {

        List<String> lists = new ArrayList<String>();
        //添加元素
        lists.add("hello");
        lists.add("hello");
        lists.add("World");

        //一次性添加
        List<String> list2 = new ArrayList<>();
        list2.addAll(lists);
        //遍历元素
        for (int i = 0;i<lists.size();i++){
            System.out.println(lists.get(i));
        }
        for (String s:lists){
            System.out.println(s);
        }
    }
}