ProduConsum.java

package javacodes;

import java.util.*;

public class ProduConsum{
    
    public static void main(String []args)throws InterruptedException
            
    {
        Queue q=new Queue();
        
        Producer p=new Producer(q);
        
        Consumer c=new Consumer(q);
        
        Thread pt=new Thread(p);
        
        Thread ct=new Thread(c);
        
        pt.start();             // Thread execution begins
        
        ct.start();
        
        pt.join();              // Current thread execution is paused, until specified thread is dead.
        
        ct.join();

        System.out.println("Existing main Thread");
    }
}

class Producer implements Runnable {

    Queue queue;

    Producer(Queue queue) {
        this.queue = queue;

    }

    public void run() {
        int i = 0;

        while (i <= 20) {
            queue.set(i);

            i++;
        }
        System.out.println("Existing Producer Thread");

        queue.producerAlive = false;
    }
}

class Consumer implements Runnable {

    Queue queue;

    Consumer(Queue queue) {
        this.queue = queue;
    }

    public void run() {
        while (queue.producerAlive) {
            queue.get();
        }
        System.out.println("Existing Consumer Thread");
    }
}

class Queue {

    int n = 0;

    boolean valueset = false;

    boolean producerAlive = true;

    synchronized void get() {
        if (!valueset) {
            try {
                wait();     // Current thread will wait until notify() is invoked
                
            } catch (InterruptedException e) {

                System.out.println("Error");
            }
        }
        valueset=false;
        
        System.out.println("Got"+" "+this.n);
        
        notify();           // Wakes up thread that is waiting on Object's monitor
    }

    synchronized void set(int n) {
        if (valueset) {
            try {

                wait();

            } catch (InterruptedException e) {

                System.out.println("Value set");
            }
        }
        this.n = n;

        valueset = true;

        notify();
    }
}