Object-oriented Programming in Kotlin: A Practical Guide to Building Scalable Systems with Classes, Delegation, and Design Patterns

Have you ever felt like your code works, but it's a house of cards? You add a new feature, and something else breaks. You come back to your own project after a few months, and the logic is a tangled mess. You know the basics of Kotlin, but you feel like you're missing the secret to writing truly clean, professional-grade applications. What if you could design systems that are not just functional, but also flexible and a joy to maintain? What if you could confidently build applications that can grow and adapt to new challenges without collapsing under their own weight? This book takes you on that transformative journey. We start with the foundational question-"How do I think in objects?"-and guide you step-by-step through the principles and patterns used by senior developers to build world-class software. You will move from simply writing code to architecting it. By the end of this journey, you won't just be a Kotlin coder; you will be a Kotlin software designer, equipped with the mental models to solve complex problems with clarity and confidence. What's insideThis book is a comprehensive, hands-on tutorial that leaves no stone unturned. Inside, you will: Master the Four Pillars of OOP in a Kotlin context: Encapsulation, Abstraction, Inheritance, and Polymorphism. Go Beyond the Basics of classes, properties, and methods, exploring primary and secondary constructors, init blocks, and custom accessors. Unlock Kotlin's Specialized Class Types, including a deep dive into data, sealed, and enum classes to model state with precision and safety. Discover Why You Should Favor Composition Over Inheritance and learn how to build flexible, decoupled systems with the "has-a" relationship. Leverage Kotlin's Superpower: First-Class Delegation with the by keyword to eliminate boilerplate and write incredibly clean, expressive code. Implement Professional Design Patterns, including the Factory, Decorator, and Strategy patterns, using idiomatic Kotlin. Build a Complete Capstone Project from start to finish-a fully functional inventory management system-to apply everything you've learned in a practical, real-world scenario. Who it's meant for This book is designed for: Java developers who are migrating to Kotlin and want to understand how to apply their existing OOP knowledge in a modern, idiomatic way. Existing Kotlin developers who know the syntax but want to deepen their understanding of object-oriented design principles to write more robust and scalable applications. Intermediate programmers who are ready to move beyond entry-level coding and learn the architectural skills needed to build professional software. This book assumes you have a basic understanding of programming concepts. It is not an introduction to programming itself. Stop fighting with brittle code and complex, tangled logic. It's time to build software that lasts. This book provides the blueprint. It gives you the patterns, the principles, and the practical Kotlin code to elevate your skills from a coder to an architect. Don't just learn another feature; master a new way of thinking. Unlock the full potential of object-oriented design in Kotlin. Scroll up and grab your copy today to begin your journey.