A very simple wait/notify example

WaitNotifyExample..java

public class WaitNotifyExample {

  public static void main(String[] args) {
		Integer lock = new Integer(0);
		Thread waiter = new Thread(new Waiter(lock));
		waiter.start();
		Thread notifier = new Thread(new Notifier(lock));
		notifier.start();
	}

}

class Waiter implements Runnable {

	public Integer lock;

	public Waiter(Integer lock) {
		this.lock = lock;
	}

	public void run() {
		synchronized (lock) {
			try {
				System.out.println("Waiter is now waiting on the lock");
				lock.wait();
				System.out.println("Waiter just got notified!");
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}

class Notifier implements Runnable {

	public Integer lock;

	public Notifier(Integer lock) {
		this.lock = lock;
	}

	public void run() {
		synchronized (lock) {
			try {
				// sleep!
				Thread.sleep(1000);
				System.out.println("About to notify the waiter..");
				lock.notify();
				System.out.println("Done notifying the waiter.");
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}