Joining another thread

gistfile1.java

import java.util.Random;

class Runner implements Runnable {
	public void run() {
		int c = 0;
		while (c++ < 10000)
			if (c % 100 == 0)
				System.out.println("still at " + c);
	}
}

public class Waiter implements Runnable{
	
	int myID;
	Random gen;
	Thread wtr;
	
	public Waiter(int anID, Thread w) {
		myID = anID;
		gen = new Random();
		wtr = w;
	}
		
	public void run() {
		System.out.println("waiting for runner to be done");
		try {
			wtr.join();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		System.out.println("Running thread " + myID);
		
		int count = 0;
		while(true) {
			System.out.println(myID +": At " + count++);
			try {
				Thread.sleep(Math.abs(gen.nextInt())%3 * 1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
	public static void main(String[] args) {
		Thread t1 = new Thread(new Runner());
		t1.start();
		Thread t2 = new Thread(new Waiter(2, t1));
		t2.start();
	}
}