Applied Kotlin. Applied Programming in Kotlin

Introduction

The book "Applied Kotlin" by James Hobbs, published in 2020, is a practical guide to the Kotlin programming language. Unlike many introductory textbooks, this book is aimed at readers already familiar with the basics of programming and seeks to show how to apply Kotlin to solve real-world problems. The volume is 340 pages, which allows for a sufficiently deep exploration of key topics without unnecessary fluff. The title fully reflects the content: the emphasis is on applied use, rather than theory for theory's sake.

What the Book is About

The book covers a wide range of topics, from basic language constructs to advanced concepts such as coroutines, DSLs, and Java interoperability. The main sections include:

• Basics of syntax and data types
• Higher-order functions and lambda expressions
• Working with collections and sequences
• Null safety and elegant error handling
• Coroutines for asynchronous programming
• Creating domain-specific languages (DSLs)
• Interacting with Java code and using libraries
• Testing and profiling applications

Each chapter contains code examples that can be immediately tried out in a development environment. The author consistently guides the reader from simple examples to more complex ones, without overloading with unnecessary details.

Who This Book is For

The book is intended for developers who already have experience programming in Java or another object-oriented language and want to learn Kotlin. It will be useful for:

• Android developers looking to switch from Java to Kotlin
• Backend developers using the JVM ecosystem
• Senior students studying modern programming languages
• Anyone who wants to understand how to apply Kotlin in real projects

The book may seem difficult for programming beginners, as the author assumes knowledge of basic concepts (classes, inheritance, exceptions).

What the Reader Will Learn

After reading the book, the reader will be able to:

• Write concise and expressive code in Kotlin
• Use functional language features (map, filter, reduce)
• Work with coroutines to create asynchronous applications
• Build DSLs to simplify configuration and describe business logic
• Integrate Kotlin code with existing Java projects
• Conduct unit testing and performance profiling
• Apply Kotlin idioms to improve code readability and reliability

Strengths

One of the main advantages of the book is its practical focus. Each concept is supported by an example that can be run and modified. The author pays attention not only to syntax but also to best practices, which helps avoid common mistakes. The chapter on coroutines deserves special mention — it is written accessibly and contains real-world usage scenarios (network requests, parallel computations). The book is also well-structured: the material is divided into logical blocks, and each chapter ends with brief conclusions.

Another plus is the emphasis on Java compatibility. The author shows how to gradually introduce Kotlin into an existing project without breaking old code. This is especially valuable for teams that cannot afford a complete migration to a new language.

The book is written in a lively style, without excessive academicism. The code examples are well-formatted and accompanied by comments.

Who It Is Recommended For

I recommend this book to anyone who wants not just to learn Kotlin syntax, but to learn how to apply it in real development. It will be useful both for individual developers and for teams planning a migration from Java. If you already write in Kotlin but want to deepen your knowledge in the area of coroutines or DSLs, the book will also provide a lot of useful information. However, if you are just starting your journey in programming