Thread is not acquiring monitor after notify calls

I just made one producer and one consumer thread. When list is empty consumer went to waiting state, then producer insert an item in list and calls notify() to invoke consumer thread but consumer is not invoking. It remains in waiting state.

Code that I have tried is:

package xs;

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

public class TestMain {
    public static void main(String[] args) {
        product pro = new product();
        producer produce = new producer(pro);
        consumer consume = new consumer(pro);
        Thread thr1 = new Thread(produce, "Producer");
        Thread thr2 = new Thread(consume, "consumer");
        thr1.start();
        thr2.start();
    }
}

class product{
    List<Date> list;
    public product() {
        list = new ArrayList<Date>();
    }

    public void produce(Date i){
        list.add(i);
    }

    public Date consume(){
        return list.remove(0);
    }
}

class producer implements Runnable{
    product product;
    @Override
    public void run() {
        while(true){
            synchronized (this) {
                while(product.list.size() == 2){
                    try {
                        wait();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
                product.produce(new Date());
                System.out.println("Produced "+product.list.size());
                notify();
            }
        }
    }


    public producer(product product) {
        this.product = product;
    }

}

class consumer implements Runnable{
    product product;
    @Override
    public void run() {
        // TODO Auto-generated method stub
        while(true){
            synchronized (this) {
                notify();
                while(product.list.size() == 0){
                    try {
                        System.out.println("Going to wait..."+ product.list.size());
                        wait();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
                System.out.println("consumed"+ product.consume());
            }
        }
    }

    public consumer(product product) {
        this.product = product;
    }
}

Output it's giving:

Going to wait...0
Produced 1
Produced 2

As you can see consumer is not coming in action after wait() call.