Kotlin Tutorial

1. Kotlin Introduction

What Kotlin is, its JVM interop and role as the default Android language, and your first program.

2. Kotlin Syntax & Variables

val vs var, null safety with ?, ?: and !!, the when expression, and string templates.

3. Functions & OOP in Kotlin

Default and named arguments, classes, data classes, and extension functions.

4. Null Safety in Depth

Chaining safe calls, the let/also/run scope functions, and platform types when calling Java code.

5. Kotlin Coroutines

Suspend functions, launch and async, structured concurrency, and a first look at Flow.

6. Kotlin for Android Basics

Data classes as models and sealed classes for UI state — the language-level patterns Kotlin brings to Android.

7. Testing in Kotlin

JUnit 5 in Kotlin, backtick test names, Kotlin assertion style, and testing with a hand-written fake dependency.

8. Kotlin Interview Questions

Commonly asked Kotlin interview questions on null safety, data classes, extension functions, and coroutines.