Method Overloading vs Method Overriding in Java

1. Introduction

In Java, method overloading and method overriding are key concepts of polymorphism.

• Overloading → Same method name, different parameters (Compile-time polymorphism)

• Overriding → Same method, same parameters, different implementation (Runtime polymorphism)

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2. Method Overloading

Explanation

• Multiple methods with the same name but different parameter lists

• Occurs within the same class

• Decision is made at compile-time

Rules

• Method name must be same

• Parameters must differ (type, number, or order)

• Return type alone is NOT enough

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3. Example of Method Overloading

class Calculator {

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

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

    double add(double a, double b) {
        return a + b;
    }
}

public class OverloadingExample {
    public static void main(String[] args) {
        Calculator c = new Calculator();

        System.out.println(c.add(10, 20));
        System.out.println(c.add(10, 20, 30));
        System.out.println(c.add(10.5, 20.5));
    }
}

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4. Explanation of Code

• Same method add() used in different ways

• Compiler decides which method to call based on arguments

Output:

30
60
31.0

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5. Method Overriding

Explanation

• Subclass provides a specific implementation of a method already defined in parent class

• Occurs between parent and child classes

• Decision is made at runtime

Rules

• Method name must be same

• Parameters must be same

• Must have inheritance

• Cannot reduce access level

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6. Example of Method Overriding

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

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

public class OverridingExample {
    public static void main(String[] args) {
        Animal a = new Dog();
        a.sound();
    }
}

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7. Explanation of Code

• Dog overrides sound() method

• Method call is decided at runtime → dynamic binding

Output:

Dog barks

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8. Key Differences Table

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9. Real-Time Example

• Overloading → Calculator methods (add, multiply with different inputs)

• Overriding → Payment system:

  • Parent: pay()

  • Child: UPI, Card → different implementations

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10. Summary

• Overloading → Same name, different parameters (Compile-time)

• Overriding → Same method, different behavior (Runtime)

• Overloading improves readability

• Overriding supports runtime flexibility

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