如何把数值或者对象添加到ArrayList集合

public class ArrayListDemo1 {
  public static void main(String[] args) {
    // 创建Random 对象
    Random random = new Random();

    // 创建ArrayList 对象
    ArrayList<Integer> list = new ArrayList<>();

    // 添加随机数到集合
    for (int i = 0; i < 6; i++) {
      int r = random.nextInt(33) + 1;
      list.add(r);
    }

    // 遍历集合输出
    for (int i = 0; i < list.size(); i++) {
      System.out.println(list.get(i));
    }
  }
}

public class TestStudent {
    public static void main(String[] args) {
        //创建集合对象
        ArrayList<Student> list = new ArrayList<Student>();
        //创建学生对象
        Student s1 = new Student("赵丽颖",18);
        Student s2 = new Student("唐嫣",20);
        Student s3 = new Student("景甜",25);
        Student s4 = new Student("柳岩",19);

        //把学生对象作为元素添加到集合中
        list.add(s1);
        list.add(s2);
        list.add(s3);
        list.add(s4);
        //遍历集合

        for(int x = 0; x < list.size(); x++) {
            Student s = list.get(x);
            System.out.println(s.getName()+"‐‐‐"+s.getAge());
        }
    }
}