Inheritance - Constructors

[timo corn]

3. class Building {
4. Building() { System.out.print("b "); }
5. Building(String name) {
6. this(); System.out.print("bn " + name);
7. }
8. }
9. public class House extends Building {
10. House() { System.out.print("h "); }
11. House(String name) {
12. this(); System.out.print("hn " + name);
13. }
14. public static void main(String[] args) { new House("x "); }
15. }

Can you explain why b is outputted and not bn as well? The subclass constructors output is logical. The constructor of subclass is called with argument in main.

[E Armitage]

When this(); is called on line 12 it calls the constructor on line 10

  House() { System.out.print("h "); } 

This constructor immediately calls the super class constructor because of the implicit call to super and that calls the constructor on line 4

Building() { System.out.print("b "); } 

. At no point is the constructor on line 5 invoked so "bn" is never printed out.