Overloading vs. Overriding: How Does Polymorphism Relate to Both in Java?

Understanding Polymorphism, Overriding, and Overloading in Java

When discussing polymorphism in Java, it's crucial to differentiate between overloading and overriding. Overloading involves defining multiple methods with the same name but different parameters, while overriding occurs when a subclass implements a method from its superclass.

Regarding the question of classifying polymorphism as overloading or overriding, neither is entirely correct. Polymorphism incorporates both concepts.

Abstract Base Classes and Overriding

Polymorphism is best exemplified through abstract base classes, which declare methods without implementing them. Subclasses then define these methods specific to their inheritance. This process is considered overriding, as the subclass provides its own implementation for the inherited method.

For instance, consider the abstract base class Human with an abstract method goPee(), representing a generic human going to the bathroom. The subclasses Male and Female override this method with specific implementations:

public abstract class Human {
    public abstract void goPee();
}

public class Male extends Human {
    @Override
    public void goPee() {
        System.out.println("Stand Up");
    }
}

public class Female extends Human {
    @Override
    public void goPee() {
        System.out.println("Sit Down");
    }
}

By creating an ArrayList containing instances of Human, we can invoke the goPee() method polymorphically, resulting in different outputs based on the specific subclass:

ArrayList<Human> group = new ArrayList<>();
group.add(new Male());
group.add(new Female());

for (Human person : group) person.goPee();

This illustrates the versatility of polymorphism in enabling the use of a common method across different objects, despite their specific implementations.

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