多线程 ---过火车问题

public class TrainTraffic {
    public static void main(String[] args) {
        Cave cave = new Cave();
        Car car1 = new Car(cave, "马车", 1000);
        Car car2 = new Car(cave, "汽车", 3000);
        Car car3 = new Car(cave, "火车", 5000);
        car1.start();
        car2.start();
        car3.start();


    }
}

//山洞类
class Cave {
    //汽车通过方法
    public synchronized void crossCar(Car car) {
        try {
            System.out.println(car.name + "in....");
            Thread.sleep(car.time);
            System.out.println(car.name + "out....");
        } catch (Exception e) {

        }
    }
}


class Car extends Thread {
    public int time;
    public String name;
    public Cave cave;

    public Car(Cave cave, String name, int time) {
        this.name = name;
        this.time = time;
        this.cave = cave;
    }

    public void run() { // 在 run 方法中 运行  同步代码块/（静态）同步方法。 在同步代码块/(静态）同步方法中，对要需要保证同步的资源进行修改。保证互斥性。
        cave.crossCar(this);
    }
}