The Producer-Consumer Relationship

//Listing 3-1. The Producer-Consumer Relationship Version 1
public class PC
{
    public static void main(String[] args)
    {
        Shared s = new Shared();
        new Producer(s).start();
        new Consumer(s).start();
    }
}

class Shared
{
    private char c;
    private volatile boolean writeable = true;
    synchronized void setSharedChar(char c)
    {
        while (!writeable)
        try
        {
         wait();
        }
        catch (InterruptedException ie)
        {
        }
        this.c = c;
        writeable = false;
        notify();
    }
    synchronized char getSharedChar()
    {
        while (writeable)
        try
        {
         wait();
        }
        catch (InterruptedException ie)
        {
        }
        writeable = true;
        notify();
        return c;
    }
}

class Producer extends Thread
{
    private final Shared s;
    Producer(Shared s)
    {
     this.s = s;
    }
    @Override
    public void run()
    {
        for (char ch = 'A'; ch <= 'Z'; ch++)
        {
            s.setSharedChar(ch);
            System.out.println(ch + " produced by producer.");
        }
    }
}
class Consumer extends Thread
{
    private final Shared s;
    Consumer(Shared s)
    {
     this.s = s;
    }
    @Override
    public void run()
    {
        char ch;
        do
        {
            ch = s.getSharedChar();
            System.out.println(ch + " consumed by consumer.");
        }
        while (ch != 'Z');
    }
}