Erro com Thread + Robot

Exception in thread "Thread-5" java.lang.NullPointerException
	at main.NovaClasse$1.run(NovaClasse.java:68)

public void loop() {
        new Thread() {
            Robot robot;
            public void run() {
                while (iniciado) {
                    robot.keyPress(KeyEvent.VK_W);
                    robot.delay(100);
                }
                robot.keyRelease(KeyEvent.VK_W);
            }
        }.start();
    }