Question 146
Given:
1. class ClassA {
2. public int numberOfinstances;
3. protected ClassA(int numberOfinstances) {
4. this.numberOflnstances = numberOfinstances;
5. }
6. }
7. public class ExtendedA extends ClassA {
8. private ExtendedA(int numberOfinstances) {
9. super(numberOflnstances);
10. }
11. public static void main(String[] args) {
12. ExtendedA ext = new ExtendedA(420);
13. System.out.print(ext.numberOflnstances);
14. }
15. }
Which is true?
A. 420 is the output.
B. An exception is thrown at runtime.
C. All constructors must be declared public.
D. Constructors CANNOT use the private modifier.
E. Constructors CANNOT use the protected modifier.
答案居然是A- -12行怎么能通过编译的?
构造函数为private啊~~~
Given:
1. class ClassA {
2. public int numberOfinstances;
3. protected ClassA(int numberOfinstances) {
4. this.numberOflnstances = numberOfinstances;
5. }
6. }
7. public class ExtendedA extends ClassA {
8. private ExtendedA(int numberOfinstances) {
9. super(numberOflnstances);
10. }
11. public static void main(String[] args) {
12. ExtendedA ext = new ExtendedA(420);
13. System.out.print(ext.numberOflnstances);
14. }
15. }
Which is true?
A. 420 is the output.
B. An exception is thrown at runtime.
C. All constructors must be declared public.
D. Constructors CANNOT use the private modifier.
E. Constructors CANNOT use the protected modifier.
答案居然是A- -12行怎么能通过编译的?
构造函数为private啊~~~
你的main()方法在ExtendedA这个类中,自然可以使用它的构造函数。这种题目,敲一遍,跑一下就知道了。事实胜于雄辩。