public class TL {
    public synchronized void waitOne() {
        try {
            Thread.sleep(1000);
        } catch (Exception e) {
        }
        waitTwo();
    }

    public synchronized void waitTwo() {
        try {
            Thread.sleep(1000);
        } catch (Exception e) {
        }
        waitOne();
    }

    private class TOne extends Thread {
        public void run() {
            System.out.println("tone started");
            waitOne();
            System.out.println("tone finished");

        }
    }

    private class TTwo extends Thread {
        public void run() {
            System.out.println("ttwo started");
            waitTwo();
            System.out.println("ttwo finished");
        }
    }

    public void doo() {
        TOne t1 = new TOne();
        TTwo t2 = new TTwo();
        t1.start();
        t2.start();
        while (t1.isAlive() || t2.isAlive()) {
            try {
                Thread.sleep(100);
            } catch (Exception e) {
            }
        }
        System.out.println("Done");
    }
    public static void main(String[] args) {
        new TL().doo();
    }

}