Monitores em Java

MonitorTester.java

import java.util.Random;

class MyMonitor {

    private int data = 0;
    private int turn = 1;

    public synchronized void update(int id) throws InterruptedException {

        while(turn != id)
            wait();

        System.out.println("Thread ID = " + id + " vai atualizar ...");
        data++; Thread.currentThread().sleep(new Random().nextInt(3000));
        System.out.println("Thread ID = " + id + " atualizou...");      
        
        turn = (turn + 1) % 2;
        notify();    
    }
}

class MyThread extends Thread {
    
    int id;
    MyMonitor myMonitor;
    
    public MyThread(int id, MyMonitor myMonitor) {
        this.id = id;
        this.myMonitor = myMonitor;
    }
    
    public void run() {
        while (true) {
            try {
                myMonitor.update(id);
                Thread.currentThread().sleep(new Random().nextInt(3000));
            }
            catch (InterruptedException ie) { 
                ie.printStackTrace(); 
            }
        }
    }
}