Main.java

import java.util.Random;

/**
 * Created by mac on 2/13/17.
 */
public class Main {
    public static void main(String[] args) {

        Message message = new Message();
        (new Thread(new Writer(message))).start();
        (new Thread(new Reader(message))).start();


    }
}

class Message {
    private String message;
    private boolean empty = true;

    public synchronized String read(){
        while(empty){
            try{
                wait();
            } catch(InterruptedException e){

            }

        }
        empty = true;
        notifyAll();
        return message;

    }

    public synchronized void write(String message){
        while(!empty){
            try{
                wait();
            }catch(InterruptedException e){

            }

        }
        empty = false;
        this.message = message;
        notifyAll();

    }
}

class Writer implements Runnable{
    private Message message;

    public Writer(Message message){
        this.message = message;
    }

    public void run()
    {
        String messages[] = {
                "Humpty Dumpty sat on a wall",
                "Humty Dumpty had a great fall",
                "All the king's horses and all the men",
                "Couldn't put Humpty together again"
        };

        //create instance of a random class so we could have a random delay

        Random random = new Random();

        for(int i =0; i<messages.length; i++){
            message.write(messages[i]);

            try{
                Thread.sleep(random.nextInt(2000));
            } catch (InterruptedException e){

            }
        }

        message.write("Finished");
    }}

    class Reader implements Runnable{
        private Message message;

        public Reader(Message message){
            this.message = message;

        }

        public void run(){
            Random random = new Random();

            for(String latestMessage = message.read(); !latestMessage.equals("Finished");

                latestMessage = message.read()) {
                System.out.println(latestMessage);
                try{
                    Thread.sleep(random.nextInt(2000));
                } catch(InterruptedException e){

                }
            }




        }
    }