問題詳情
58.Given: 10. interface Foo{} 11. class Alpha implements Foo{} 12. class Beta extends Alpha{} 13. class Delta extends Beta{ 14. public static void main(String[] args){ 15. Beta x = new Beta()； 16. //insert code here 17. } 18. } Which code, inserted at line 16, will cause a java.lang.ClassCastException?
(A) Alpha a = x；
(B) Foo f = (Delta)x；
(C) Foo f = (Alpha)x；
(D) Beta b = (Beta)(Alpha)x；
參考答案