5-3作业问题

package com.imooc.xc;
public class Weather {
 private int temperature;//温度
 private int humidity;//湿度
 boolean flag=false;
 public synchronized void generate(){
  if(flag){
   try {
    wait();
   } catch (InterruptedException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   this.setTemperature((int)(Math.random()*40+1));
   this.setHumidity((int)(Math.random()*100+1));
   flag=true;
   System.out.println("产生天气数据[温度："+this.temperature+",湿度："+this.humidity+"]");
   notifyAll();
  }
 }
 public synchronized void read(){
  if(!flag){
   try {
    wait();
   } catch (InterruptedException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
  this.getTemperature();
  this.getHumidity();
  System.out.println("读取天气数据[温度："+temperature+",湿度："+humidity+"]");
  flag=false;
  notifyAll();
 }
 public int getTemperature() {
  return temperature;
 }
 public void setTemperature(int temperature) {
  this.temperature = temperature;
 }
 public int getHumidity() {
  return humidity;
 }
 public void setHumidity(int humidity) {
  this.humidity = humidity;
 }
}

package com.imooc.xc;

public class GenerateWeather implements Runnable{
  Weather weather;
  GenerateWeather(Weather weather){
   this.weather=weather;
  }
 @Override
 public void run() {
  int i=0;
  while(i<100){
   weather.generate();
  i++;
  }
  try {
   Thread.sleep(5000);
  } catch (InterruptedException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

}

package com.imooc.xc;

public class ReadWeather implements Runnable{
  Weather weather;
  ReadWeather(Weather weather){
   this.weather=weather;
  }

 @Override
 public void run() {
  int i=0;
  while(i<100){
   weather.read();
  i++;
  }
  try {
   Thread.sleep(100);
  } catch (InterruptedException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

}

package com.imooc.xc;

public class WeatherTest {
 public static void main(String[] args) {
  Weather weather=new Weather();
  new Thread(new GenerateWeather(weather)).start();
  new Thread(new ReadWeather(weather)).start();
 }

}

错在哪里，为啥输出不来啊？求解