Java buffer class producer consumer example question

class buffer
{
    private int data;//cake
    private boolean empty=true;//show cake is empty
    Public synchronized get()//How to buy a cake
    {
        while(empty)
        {
            try {
                wait();
            } } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        empty=true;
        notifyAll();//Wake up the producer
        return data;
    }
    Public synchronized void put(int data) {// Method for producing cakes
        while(!empty)
        {
            try {
                wait();
            } } catch (InterruptedException e) {
                e.printStackTrace();
            }
            empty=false;
            notifyAll();//Wake up consumers
            this.data=data;
        }
    }
}
class Producer extends Thread 
{
    private Buffer buffer;
    public Producer(Buffer buffer)
    {
        this.buffer=buffer;
    }
    public void run()
    {
        for(int i=0;i<=10;i++)
        {
            buffer.put(i);//cake production
            System.out.println ("Producer"+i+"Produce Cake");
            try {
                Thread.sleep(1000);
            } } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}
class Cusumer extends Thread 
{
    private Buffer buffer;
    public Cusumer(Buffer buffer)
    {
        this.buffer=buffer;
    }
    public void run()
    {
        for(int i=0;i<=10;i++)
        {
            int data=buffer.get();//consumption
            System.out.println ("Consumers consume "+data+"th cake");
            try {
                Thread.sleep(1000);
            } } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}
public class Ex01 {

    public static void main(String[] args) {
        Buffer obj = new Buffer();
        Producer p1 = new Producer(obj);
        Cusumer c1 = new Cusumer(obj);
        p1.start();
        c1.start();

    }

}

``When I produce the first cake with buffer class, the consumer consumes the first cake
Strangely, only producers and consumers are not coming up, so what did I leave out?