What role does polymorphism play in object-oriented programming?

Polymorphism in object-oriented programming allows objects of different classes to be processed through a single interface, while each object can implement behavior in its own way. This provides flexibility and extensibility of the code.

The role of polymorphism:

• Allows writing generic code that works with a base type, with specific behavior defined in subclasses.
• Simplifies support and extension of the system — new classes can be added without modifying existing code.
• Promotes the implementation of the open/closed principle.

Example in Java:

interface Animal {
    void makeSound();
}

class Dog implements Animal {
    public void makeSound() {
        System.out.println("Woof");
    }
}

class Cat implements Animal {
    public void makeSound() {
        System.out.println("Meow");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal animal = new Dog();
        animal.makeSound(); // Outputs "Woof"

        animal = new Cat();
        animal.makeSound(); // Outputs "Meow"
    }
}

Here, the same call to makeSound() behaves differently depending on the actual type of the object.