【Java每日一题】20161108

package Nov2016;

import java.util.TreeSet;

public class Ques1108 {
    public static void main(String[] args){

        Animal dog = new Animal("dog");
        Animal cat = new Animal("cat");

        TreeSet<Animal> animals = new TreeSet<Animal>();
        animals.add(dog);
        animals.add(cat);

        System.out.println(animals);  //
    }
}

// 动物类
class Animal implements Comparable<Animal>{
    private String name;

    Animal(String name){
        this.name = name;
    }

    @Override
    public int compareTo(Animal o){
        return 0;
    }

    @Override
    public String toString(){
        return name;
    }
}

今日问题： 
请问注释1处输出结果是什么？（点击以下“【Java每日一题】20161108”查看20161107问题解析）

题目原发布于公众号、简书：【Java每日一题】20161108，【Java每日一题】20161108 
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