面向对象多态性

abstract class TakeOffSystem {
    public abstract void fly();
    public abstract void land();
}

class BattlePlan extends TakeOffSystem{
    public void fly(){
        System.out.println("战斗机起飞了");
    }
    public void land(){
        System.out.println("战斗机降落了");
    }
}

class HeliCopter extends TakeOffSystem{
    public void fly(){
        System.out.println("直升机起飞了");
    }
    public void land(){
        System.out.println("直升机降落了");
    }
}
class GunDam extends TakeOffSystem{
    public void fly(){
        System.out.println("高达起飞了");
    }
    public void land(){
        System.out.println("高达降落了");
    }
}
public class FlyTest{
    public static void main(String[] args) {
        TakeOffSystem a = new BattlePlan();
        TakeOffSystem b = new HeliCopter();
        TakeOffSystem c = new GunDam();
        a.fly();
        a.land();
        b.fly();
        b.land();
        c.fly();
        c.land();
    }
    
}