JAVA中，怎么比较多个对象的大小？

实现Comparable接口，然后把所有的对象加到一个ArrayList中，然后用Collections.sort排序

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Compare {
public static void main(String[] args) {
Student stu1 = new Student("stu1",10,150);
Student stu2 = new Student("stu2",9,140);
Student stu3 = new Student("stu3",10,160);
Student stu4 = new Student("stu4",10,140);
Student stu5 = new Student("stu5",11,152);
Student stu6 = new Student("stu6",12,151);
Student stu7 = new Student("stu7",8,140);
Student stu8 = new Student("stu8",10,156);
Student stu9 = new Student("stu9",11,149);
Student stu10 = new Student("stu10",10,155);
Student stu11 = new Student("stu11",13,152);
List<Student> list = new ArrayList<Student>();
list.add(stu1);