Possible to avoid default call to super() in Java?

Question

Assume for some reason that I don't want to implicitly call super() which is done by default.

class Animal {
    public Animal() {
        System.out.println("Constructing an animal.");
    }
}
class Dog extends Animal {
    public Dog() {
        System.out.println("Constructing a dog.");
    }
    public static void main(String[] a) {
        new Dog();
    }
}

Is there any way to "disable" the default behavior that super() is invoked when making a new Dog? Or would that be principally and conceptually wrong?

I mean there could be cases where you would want only the constructor of the subclass and not invoke the construction of the baseclass, and still inherit the baseclass.

Answer 1

If I understand you correctly you want to override the behavior of the Animal constructor or just not call it. If so you're conceptually wrong: you always need to call a super constructor, the only thing you could to with the calls is provide a non-default constructor, i.e. one with arguments and provide appropriate arguments to influence the behavior of that constructor (e.g. by either selecting a different constructor, passing some sort of strategy/function object etc.)

Another way might be to provide some init() method that the default constructor is calling and which you can override but there are a few problems with it, e.g.:

• If the overridden method tries to access anything only visible to the subclass (e.g. additional fields) you could run into problems because those haven't been initialized yet.
• That method can't initialize any final field.