java100-集合类简介

//集合类的作用
 public class test35 {
     private String name;
     private int num;
     private int grade;
     public test35(String name,int num,int grade){
         this.name=name;
         this.num=num;
         this.grade=grade;
     }
     public String getName() {
         return name;
     }
     public int getGrade() {
         return grade;
     }
     public int getNum() {
         return num;
     }
 }
 测试import java.util.ArrayList;
public class test36 {
     public static void main(String[] args){
         ArrayList aa1=new ArrayList();
         //当前对象个数
         System.out.println("原始的对象个数为"+aa1.size());
         test35 xs1=new test35("歌谣",3,4);
         aa1.add(xs1);
         System.out.println("现在的对象个数为"+aa1.size());
     }
 }