Performance of Kotlin Applications: Code Optimization, Profiling, and Best Practices

The book "Performance of Kotlin Applications" is a practical guide for developers who want to write truly fast and efficient code in the Kotlin language. Unlike most textbooks that teach syntax, this book focuses on performance bottlenecks, profiling, and fine-tuning applications.

The author, Alexey Igoryev, a senior developer with 10 years of experience in the JVM ecosystem, shares real-world cases and approaches that will help you reduce application response time, decrease memory consumption, and avoid common pitfalls when working with Kotlin.

Who is this book for?

• For Kotlin developers who already write code but want to understand why it runs slowly.
• For Java programmers transitioning to Kotlin who want to avoid performance-related anti-patterns.
• For technical leads and architects responsible for the quality and speed of server-side and Android applications.
• For anyone who wants to understand the workings of the JVM, JIT compilation, and garbage collection in the context of Kotlin.

What will you learn from the book?

• Profiling basics: how to use JProfiler, VisualVM, and built-in IntelliJ IDEA tools to find bottlenecks.
• Memory management: how Kotlin interacts with the GC, why inline functions can be dangerous, and how to avoid memory leaks.
• Coroutine optimization: configuring dispatchers, minimizing overhead when launching coroutines, working with threads.
• Working with collections: why sequences are not always faster than lists, and how to choose the right data structure.
• JIT compilation and bytecode: how Kotlin code is transformed into bytecode, and which patterns speed up execution.
• Performance testing: writing benchmarks with JMH and integrating tests into CI/CD.

Why should you read this book?

Kotlin is a powerful language, but its flexibility (lambdas, extension functions, sealed classes) can lead to unexpected performance issues. This book will help you write not just working code, but code that flies. You will learn to measure performance, make informed optimization decisions, and avoid premature optimization.

The book contains numerous code examples that can be immediately applied in real projects. Each chapter concludes with practical tasks and checklists for auditing existing code.

Suitable for Kotlin version 1.9+ and modern JVM versions (17+).