Kotlin Interview: 200 Questions and Answers

The book "Kotlin Interview: 200 Questions and Answers" is a practical guide for anyone who wants to confidently pass a technical interview for a Kotlin developer position. The author has compiled the most frequently asked questions in IT company interviews and provided detailed, structured answers.

The book covers all key topics of the Kotlin language and related technologies. You will find questions on:

• Syntax basics — data types, functions, classes, objects, sealed classes, data classes;
• Object-oriented programming — inheritance, interfaces, abstract classes, delegation;
• Functional programming — lambdas, higher-order functions, inline functions, collections and Sequence;
• Null Safety and Type System — nullable types, Elvis operator, safe call, smart casts;
• Coroutines and asynchrony — CoroutineScope, launch, async, Dispatchers, Flow, Channels;
• Java interoperability — compatibility, annotations, calling Java from Kotlin and vice versa;
• Testing — JUnit, MockK, testing coroutines;
• Best practices and architecture — Clean Architecture, MVVM, DI (Dagger, Koin).

Each question is accompanied not only by the correct answer but also by an explanation of why it is important, along with code examples. This helps not just to memorize answers but to deeply understand the language concepts.

The book will be useful for:

• Junior developers who are just starting their journey in Kotlin and want to systematize their knowledge;
• Middle developers who are preparing for a promotion or moving to another company;
• Team leads and architects who conduct interviews and want to refresh their list of questions;
• Students and graduates planning a career in Android development or JVM backend.

Special attention is given to Android development questions (Jetpack Compose, ViewModel, Lifecycle), but the book is not limited to the mobile platform — it is also suitable for server-side Kotlin (Ktor, Spring Boot).

The "question-answer" format allows you to quickly find the desired topic and review the material before an interview. The book is written in a lively, understandable language, without excessive academicism. All code examples are relevant for the latest versions of Kotlin (1.9+).

If you want to feel confident in an interview and get an offer from a good company, this edition will be your reliable assistant.