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

class Rabbit{
    int age;
    public Rabbit(){
        this.age=1;
    }
    public boolean createBaby(){
        age++;
        if(age>=3){
            return true;
        }
        else{
            return false;
        }
        
    }
}
public class Home implements Runnable{
    static List<Rabbit> lr;
    int countOfMonth = 0;
    public Home(int com){
        this.countOfMonth = com;
        Rabbit r = new Rabbit();
        lr = new ArrayList<Rabbit>();
        lr.add(r);
    }
    @Override
    public void run(){
        int count=0;
        while(count<countOfMonth){
            System.out.println(lr.size());
            try {
                Thread.sleep(1000);
                count++;
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            int newBabyCount=0;
            for(Rabbit r:lr){
                if(r.createBaby()){
                    newBabyCount++;
                }
            }
            for(int i=1;i<=newBabyCount;i++){//不好意思，刚才数据并发了。
                lr.add(new Rabbit());
            }
        }
    }
    public static void main(String args[]){
        Home h = new Home(10);
        new Thread(h).start();
    }
}

------解决方案--------------------
Java code
package com;

import java.util.Scanner;

public class Rabbit {
    
    public static void main(String[] args) {
        Rabbit rabbit = new Rabbit();
//        for(int i = 1; i <= 12; i++) {
//            System.out.println(i +  ":" + rabbit.getRabbitCount(i));
//        }
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入月数（当输入为0的时候结束）：");
        while(true) {
            try {
                String str = scanner.nextLine();
                int x = Integer.parseInt(str);
                if(x == 0) {
                    //System.exit(0);
                    break;
                }
                System.out.println(x +  ":" + rabbit.getRabbitCount(x));
            } catch(Exception e) {
                System.out.println("你输入的不是正整数");
            }
        }
    }
    
    public int getRabbitCount(int month) {
        if(month < 1) {
            throw new IllegalArgumentException();
        }
        if(month == 1 || month == 2) {
            return 1;
        } else {
            return this.getRabbitCount(month - 1) + this.getRabbitCount(month - 2);
        }
    }
}