interface Playable {
    void play();
}
interface Bounceable {
    void play();
}
interface Rollable extends Playable, Bounceable {
    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());
    }
}

你这段代码想干嘛的？

把extend改为implements
     你这到底是想干什么啊，能说来听听吗

interface Rollable extends Playable, Bounceable 错误，不可以多继承。