Constructors are not inherited but behaving strangely

Question

I have found this issue and I do not understand why constructors are being inherited in the first case. As far as I know, constructors are not inherited. Am I missing something very important ?

class Bird {
{ System.out.print("b1 ");}
public Bird() {System.out.print("b2 ");}

class Raptor extends Bird
{
    static {System.out.print("r1 ");}

    public Raptor() {System.out.print("r2 ");}

    {
        { System.out.print("r3 ");}
        static {System.out.print("r4 ");}
    }

class Hawk extends Raptor 
{    
    public static void main(String[] args)
    {    
        System.out.print("pre ");
        new Hawk();
        System.out.println("hawk ");
    }
}

The answer for the above is:

r1 r4 pre b1 b2 r3 r2 hawk

Clean up your formatting and be more specific about what you're trying to demonstrate. — shmosel, Jun 03 '16 at 02:45
That looks logical. What is the question? What do you not understand? — Jim Garrison, Jun 03 '16 at 02:47

Krease · Answer 1 · 2016-06-03T02:55:42.113

1

If you don't explicitly call the parent class constructor (via super(...)) or another constructor from the same class (via this(...)), the 0-argument parent class constructor is implicitly called.

Specifically, your code public Raptor() {System.out.print("r2 ");} implicitly calls the Bird constructor as the first thing, as if you had typed public Raptor() {super(); System.out.print("r2 ");}

Works similarly for your Hawk subclass.

edited Jun 03 '16 at 02:55

answered Jun 03 '16 at 02:47

Krease

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Thanks Elliot - updated – Krease Jun 03 '16 at 02:55

Constructors are not inherited but behaving strangely

1 Answers1