🌟 What is Abstraction in Java?

Abstraction is a concept where you hide the internal details of how something works and only show the essential features.

In Java, abstraction is implemented using:

  1. Abstract classes
  2. Interfaces

💡 Why Do We Use Abstraction?

Here’s why abstraction is useful and often necessary in Java:
1. Reduces Complexity

Abstraction helps you focus on what an object does, not how it does it. This makes code easier to understand and use.
2. Improves Maintainability

Since the internal implementation is hidden, changes to it don’t affect other parts of your program.
3. Supports Reusability and Scalability

Abstract classes and interfaces define reusable templates. You can create different implementations without changing the rest of the system.
4. Enables Loose Coupling

You can program to an interface or abstract class, which reduces dependency on specific implementations.

🕒 When Should You Use Abstraction?

Use abstraction in the following situations:
✅ When multiple classes share common behavior

If several classes have similar methods but differ in implementation, use an abstract class or interface to define the shared behavior.

Example:

abstract class Shape {
    abstract void draw();
}

Now different shapes like Circle, Rectangle, or Triangle can inherit from Shape and define their own draw() method.
✅ When building frameworks or libraries (tbd)

If you're designing a framework or API, abstraction lets you define contracts that other developers can implement without exposing internal logic.

Example:

interface Database {
    void connect();
    void disconnect();
}

Different databases like MySQL, PostgreSQL, or MongoDB can implement this interface in their own way.
✅ When you want to provide a template but restrict direct object creation

Use abstract classes when you want to provide some common code and restrict object creation.

Example:

abstract class Animal {
    abstract void sound();
}

You can’t create an Animal object directly, but subclasses like Dog or Cat can extend it and implement sound().