第一部分：

//创建学生类 public class Student {
      //成员变量     private String name;     private int age;     //构造方法     public Student(){
          super();     }     public Student(String name, int age){
          this.name = name;         this.age = age;     }     //成员方法     public String getName() {
          return name;     }     public void setName(String name) {
          this.name = name;     }     public int getAge() {
          return age;     }     public void setAge(int age) {
          this.age = age;     }     @Override     public String toString() {
          return "Student{" +                 "name='" + name + '\'' +                 ", age=" + age +                 '}';     } } 第二部分：

public class Demo10 {
      public static void main(String[] args){
          //创建一个大集合         ArrayList
    
     
      > bigArrayList = new ArrayList<>();         //创建第一个组的集合         ArrayList
      
        firstClass = new ArrayList<>();         //创建学生对象         Student s1 = new Student("乔峰",30);         Student s2 = new Student("段誉",28);         Student s3 = new Student("虚竹",25);         //添加对象         firstClass.add(s1);         firstClass.add(s2);         firstClass.add(s3);         //添加到最大的结集合中去         bigArrayList.add(firstClass);         //创建第二个组的集合         ArrayList
       
         secoundClass = new ArrayList<>();         //创建学生对象         Student s4 = new Student("唐僧",30);         Student s5 = new Student("悟空",28);         Student s6 = new Student("八戒",25);         Student s7 = new Student("沙僧",25);         //添加对象         secoundClass.add(s4);         secoundClass.add(s5);         secoundClass.add(s6);         secoundClass.add(s7);         //添加到最大的结集合中去         bigArrayList.add(secoundClass);         //遍历最大的集合         for (ArrayList
        
         array:bigArrayList){
              for (Student s:array){
                  System.out.println(s.getName()+"--------"+s.getAge());             }         }     } }