# abstract 相關問題 **題目一** 什么是抽象類 1. A class with no methods 1. A class with no concrete subclasses 1. A class with at least one undefiend message 1. None of above 答案是 4 我們是可以定義一個抽象空類的 ~~~ abstract class emptyAb {} ~~~ **題目二** ~~~ abstract class Base{ abstract public void myfunc(); } public class Abs extends Base{ public static void main(String argv[]){ Abs a = new Abs(); a.amethod(); } } public void amethod(){ System.out.println("A method"); } } ~~~ 運行的結果 1. 輸出 A method 1. The code will compile but complain at run time 1. The compiler will complain errors in Abs class 答案是 3