# abstract 相关问题 **题目一** 什么是抽象类 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 我们是可以定义一个抽象空类的 ~~~ abstract class emptyAb {} ~~~ **题目二** ~~~ 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"); } } ~~~ 运行的结果 1. 输出 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