Inicializando MotionPath e MotionTrack

public class MotionPath implements Savable {

    public static void main(String[] args) {
        MotionPath app = new MotionPath();
        app.start();//aqui dá erro
    }

public class MotionTrack extends AbstractCinematicEvent implements Control {

    public static void main(String[] args) {
        MotionTrack app = new MotionTrack();
        app.start();//aqui dá erro
    }