关于Collections.reverseOrder

虽然实现了效果，但是不知道为什么。。

package effectiveJava.reverseOrder;

import java.util.Comparator;

public class Person implements Comparator<Comparable<Object>> ,Comparable<Person>{

	int age;

	@Override
	public int compare(Comparable<Object> o1, Comparable<Object> o2) {
		return o2.compareTo(o1);
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public int compareTo(Person o) {
		if(this.age > o.age) return 1;
		else if(this.age == o.age) return 0;
		else return -1;
	}
	
	
}

package effectiveJava.reverseOrder;

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

public class TEST {

	public static void main(String[] args) {
		List<Person> list = new ArrayList<Person>();
		Person p1 = new Person();
		p1.setAge(1);
		
		Person p2 = new Person();
		p2.setAge(2);
		
		Person p3 = new Person();
		p3.setAge(3);
		
		list.add(p3);
		list.add(p1);
		list.add(p2);
		
		Comparator c = Collections.reverseOrder();
		Collections.sort(list,c);
		
		for(Person p: list){
			System.out.println(p.age);
		}
	}
}