//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());}
}

运行结果