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javadynamicpolymorphismdispatch

Polymorphism - Simple

Just confused on how to following answer is correct.

class Cat {
    public void isClawedBy(Cat c){
        System.out.println("Clawed by a cat");
    }
}

class Kitten extends Cat{
    public void isClawedBy(Kitten c){
        System.out.println("Clawed by a Kit");
    }
}

If the following is called

Cat g = new Cat();
Cat s = new Kitten();
Kitten t = new Kitten();

g.isClawedBy(t);
s.isClawedBy(t);
t.isClawedBy(t);

How is the answer: Clawed by Cat Clawed by Cat Clawed by Kitten

I'm confused on why s.isClawedBy(t) = Clawed by Cat. Since the dynamic type of s is a kitten, and t is a kitten. Is it because the arguments are different, so it doesn't override it?

Another part I am confused on. //Note the arguments have been swapped.

class Cat {
    public void isClawedBy(Kitten c){
        System.out.println("Clawed by a cat");
    }
}

class Kitten extends Cat{
    public void isClawedBy(Cat c){
        System.out.println("Clawed by a Kit");
    }
}

If the following is called

Cat g = new Cat();
Cat s = new Kitten();
Kitten t = new Kitten();

g.isClawedBy(t);
s.isClawedBy(t);
t.isClawedBy(t);

The output is: Clawed by Cat Clawed by Cat Clawed by Cat

How does it work for when t is called?

Solution

  • About the second query : t.isClawedBy(t) giving the output of Clawed by Cat.

    Since t is a Kitten and the argument passed in the method t.isClawedBy(t) is also Kitten , the method from the superclass Cat will be called because it matches the arguments perfectly.