23.Java basis _ArrayList class

 

The construction and use of the method ArrayList class

 1 import java.util.ArrayList;
 2 public class test {
 3     public static void main(String[] args) {
 4         ArrayList<String> array=new ArrayList<>();
 5         System.out.println(array); //[]
 6         //add 加到末尾
 7         array.add("hello");
 8         array.add("world");
 9         array.add("java");
10         System.out.println(array); //[hello, world, java]
11         //add 插入
12         array.add(0,"javase");
13         System.out.println(array); //[javase, hello, world, java]
14      }
15 }

 

ArrayList class common methods: