Learn KOTLIN with Real Code Examples

Kotlin reduces boilerplate while maintaining strong static typing and safety.

It offers null-safety, extension functions, and coroutines for cleaner async code.

Fully interoperable with Java, running on the JVM and compiling to Android, JS, and native.

Statically typed with inference

Coroutines for async programming

Object-oriented + functional hybrid

Extension functions and lambdas

Data/Sealed/Inline classes

Variables and null-safety

Classes, objects, and functions

Coroutines and flows

Collections and extension functions

Sealed classes and inline classes

Kotlin Multiplatform basics

src/main/kotlin for source code

build.gradle.kts for dependencies

resources/ for static assets

Android module structure for mobile

shared/ modules for KMP

Write Kotlin in .kt files

Compile with Kotlin/JVM, Kotlin/JS, or Kotlin/Native

Execute via JVM or platform runtime

Build with Gradle Kotlin DSL

Use Compose for UI when needed

Beginner: Simple Android or console apps

Intermediate: Ktor backend APIs

Advanced: Compose Multiplatform apps

Expert: Kotlin Multiplatform libraries

More concise than Java

Safer than JavaScript

More modern than C# for Android

Less low-level than Rust/Go

Kotlin 1.0 (2016) – First stable release

Kotlin 1.3 – Coroutines stable

Kotlin 1.4 – Multiplatform improvements

Kotlin 2.0 – New K2 compiler

Coroutine: Lightweight concurrency primitive

Extension Function: Add new methods to types

Data Class: Auto-generates boilerplate

Flow: Cold asynchronous stream