Polymorphism in java

Today I learned what is polymorphism in java .Polymorphism in Java is one of the core concepts in object-oriented programming (OOPS) that allows objects to behave differently based on their specific class type. The word polymorphism means having many forms.

Types of Polymorphism in Java

1.Compile-Time Polymorphism (Method Overloading)

*Achieved using method overloading (same method name, different parameters).

*Decided by the compiler.

Exam program

class Calculator {
    int add(int a, int b) {
        return a + b;
    }

    int add(int a, int b, int c) {
        return a + b + c;
    }
}

public class Main {
    public static void main(String[] args) {
        Calculator c = new Calculator();
        System.out.println("Sum of 2 numbers: " + c.add(10, 20));
        System.out.println("Sum of 3 numbers: " + c.add(10, 20, 30));
    }

}

**Output**
Sum of 2 numbers: 30
Sum of 3 numbers: 60

2.Runtime Polymorphism (Method Overriding)

*Achieved using method overriding (subclass provides its own implementation of a method already defined in parent class).

*Decided at runtime using dynamic method dispatch.

Example program

class Animal {
    void sound() {
        System.out.println("Animal makes a sound");
    }
}

class Dog extends Animal {
    @Override
    void sound() {
        System.out.println("Dog barks");
    }
}

class Cat extends Animal {
    @Override
    void sound() {
        System.out.println("Cat meows");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal a;

        a = new Dog();
        a.sound();  

        a = new Cat();
        a.sound();   
    }
}

**Output**
Dog barks
Cat meows