写出下列程序的运行结果

interface Playable {
    void play();
}

interface Bounceable {
    void play();
}

interface Rollable extends Bounceable,Playable {
    Ball ball = new Ball("PingPang");
}

class Ball implements Rollable {
    private String name;

    public String getName() {
        return name;
    }

    public Ball(String name) {
        this.name = name;
    }

    public void play() {
        ball = new Ball("Football");
        System.out.println(ball.getName());
    }
}

参考解答

编译错误

public void play() {
    ball = new Ball("Football"); // 错误
    System.out.println(ball.getName());
}

ball 的定义继承自接口Rollable，接口中定义的变量都是static 且 final 的，不能被重新赋值。