Interface Default Methods

In this problem, you will create a program that defines a default method in the Greeter interface, implements it in BasicGreeter (using the default as-is) and in FormalGreeter (overriding it), and displays the results to standard output.

Learning Objective: Understand defining and using default methods in interfaces

Overview

Define a default method in an interface and verify behavior when an implementing class uses it as-is versus overriding it.

Specifications

1. Define default void greet() in Greeter interface (prints Hello!)
2. BasicGreeter implements Greeter (uses default method as-is)
3. FormalGreeter implements Greeter, overrides greet() to print Good day!
4. In main, create objects and call greet()

Output Format

Hello!
Good day!