The famous producer/consumer example

Consumer.java

public class Consumer extends Thread {

  private IntBuffer buffer;

	public Consumer(IntBuffer buffer)
	{
		this.buffer = buffer;
	}

	public void run() {
		while (true)
		{
			int num = buffer.remove();
			System.out.println("Consumer " + num);
		}

	}
}

IntBuffer.java

public class IntBuffer {

  private int index;
	private int[] buffer = new int[10];

	public synchronized void add(int num)
	{
		while (index == buffer.length - 1)
		{
			try {
				wait();
			} catch (InterruptedException e)
			{

			}
		}

		buffer[index++] = num;
		notifyAll();
	}

	public synchronized int remove()
	{
		while (index == 0)
		{
			try {
				wait();
			} catch (InterruptedException e)
			{

			}
		}

		int ret = buffer[--index];
		notifyAll();
		return ret;

	}
}

Producer.java

public class Producer extends Thread {
  private IntBuffer buffer;

	public Producer(IntBuffer buffer) {
		this.buffer = buffer;
	}

	public void run() {
		Random r = new Random();
		while (true) {
			int num = Math.abs(r.nextInt() % 100);
			buffer.add(num);
			System.out.println("Produced " + num);
		}
	}

}