✅ Default Methods in Interface vs Abstract Class —

🔷 1. What Are Default Methods in Interfaces?

Prior to Java 8, interfaces could only have abstract methods (method signatures without implementation). This limited flexibility because adding a new method to an interface required updating all implementing classes.

Since Java 8, default methods allow concrete method implementations inside interfaces, offering backward compatibility and multiple inheritance of behavior.

interface Vehicle {
    void start();
// Default method with implementation
    default void honk() {
        System.out.println("Beep Beep!");
    }
}

🔶 2. Default Methods vs Abstract Class

🔄 3. Why Default Methods Are a Game Changer

🧨 Before Java 8:

You had to modify all implementing classes if you added a method to an interface.

🚀 After Java 8:

You can evolve interfaces without breaking backward compatibility by adding default methods.

📌 Example:

interface PaymentProcessor {
    void processPayment(double amount);
// New method added without breaking existing…