Default and static Methods

In this problem, you will create a program that defines default and static methods in a Loggable interface, and demonstrates how implementing classes can use the default method as-is or override it, displaying the results to standard output.

Learning Objective: Understand how to define and distinguish between default methods and static methods in interfaces, introduced in Java 8

Overview

Define default and static methods in a Loggable interface, and write a program that demonstrates both using the default method as-is and overriding it.

Specifications

Loggable interface

• Declare abstract method String getTag() (defined by implementing classes)
• Define default method default void log(String message) that prints in the format "[{getTag()}] {message}"
• Define static method static void info(String message) that prints in the format "[INFO] {message}"

AppLogger class (implements Loggable)

• getTag() method returns "APP"
• Uses the default log() method without overriding

DebugLogger class (implements Loggable)

• getTag() method returns "DEBUG"
• Overrides log() to print in the format ">>> [{getTag()}] {message} <<<"

Main class

1. Call Loggable.info("System started") (static method)
2. Create an AppLogger instance and call log("User logged in")
3. Create a DebugLogger instance and call log("Variable x = 42")

Output Format

[INFO] System started
[APP] User logged in
>>> [DEBUG] Variable x = 42 <<<