🧩 What is Abstraction?

Abstraction is the process of hiding internal implementation details and showing only the functionality to the user.

In Java, abstraction can be achieved using:

• Abstract Classes
• Interfaces

📘 Abstract Class

An abstract class cannot be instantiated. It can have both abstract (without body) and concrete (with body) methods.

                    abstract class Animal {
                        abstract void makeSound();
                    
                        void sleep() {
                            System.out.println("Sleeping...");
                        }
                    }
                    
                    class Dog extends Animal {
                        void makeSound() {
                            System.out.println("Dog barks");
                        }
                    
                        public static void main(String[] args) {
                            Dog d = new Dog();
                            d.makeSound();
                            d.sleep();
                        }
                    }
                    

🔌 Interface

An interface is a fully abstract type used to achieve full abstraction and multiple inheritance in Java.

                    interface Vehicle {
                        void start();
                    }
                    
                    class Car implements Vehicle {
                        public void start() {
                            System.out.println("Car is starting");
                        }
                    
                        public static void main(String[] args) {
                            Car c = new Car();
                            c.start();
                        }
                    }