Core OOP Principles Overview

Master the four pillars that define object-oriented programming. Build robust, maintainable systems using inheritance, polymorphism, encapsulation, and abstraction with clear examples and practical applications.

Abstraction and Encapsulation

Control access and protect data

Master the practice of bundling data and methods while controlling access through visibility modifiers. Learn to create clean interfaces using getters, setters, and proper data hiding techniques.

You'll learn: Access modifiers, getter/setter methods, data validation, and maintaining object integrity

Inheritance

Extend and specialize classes

Learn to create class hierarchies where child classes inherit properties and methods from parent classes. Master super and subclass relationships, method overriding, and the IS-A relationship that models real-world specialization.

You'll learn: How to extend classes, override methods, use super keyword, and design effective class hierarchies

Polymorphism

One interface, many forms

Understand how objects of different types can be treated uniformly through method overriding and dynamic binding. Write flexible code that works with multiple object types using the same interface.

You'll learn: Method overriding, runtime polymorphism, casting objects, and designing adaptable systems

Abstract Classes & Interfaces

Define contracts and common behavior

Create abstract classes that provide partial implementations and interfaces that define pure contracts. Learn when to use each approach and how they enable flexible, extensible designs.

You'll learn: Abstract classes vs interfaces, implementing contracts, multiple inheritance through interfaces, and designing flexible systems

Start here: Begin with Inheritance to understand class relationships, then move through Polymorphism and Encapsulation. Finish with Abstract Classes & Interfaces to see how these principles work together. Complete the exercises after each topic to reinforce the concepts—these principles build on each other.