Java中的向下转换抛出ClassCastException[duplicate]

Helicopter h = (Helicopter) new Rotorcraft(); )以及 throws Runtime exception 类型 ClassCastException .

基类:

public  class Rotorcraft {

protected final int height = 5;
    protected int fly(){
        return height;
    }
}

public class Helicopter extends Rotorcraft {    
    private int height = 10;

    public int fly() {
        return super.height;
    }

    public static final void main(String[] a){
        Helicopter h = (Helicopter) new Rotorcraft();
    }
}