Kotlin is a statically-typed programming language that runs on the Java virtual machine and also can be compiled to JavaScript source code or use the LLVM compiler infrastructure. Its primary development is from a team of JetBrains programmers based in Saint Petersburg, Russia. While the syntax is not compatible with Java, Kotlin is designed to interoperate with Java code and is reliant on Java code from the existing Java Class Library, such as the collections framework. Kotlin uses aggressive type inference to determine the type of values and expressions for which type has been left unstated. This reduces language verbosity relative to Java, which demands often entirely redundant type specifications.

As of Android Studio 3.0 Kotlin is a fully supported programming language on Android and lets the user choose between targeting Java 6- or Java 8-compatible bytecode.


Table of Content

Kotlin for Server Side
Kotlin for Android
Kotlin for JavaScript
Kotlin for Native
Coroutines
Multiplatform
What's New in 1.1
What's New in 1.2
What's New in 1.3
Basic Syntax
Idioms
Coding Conventions
Basic Types
Packages and Imports
Control Flow
Returns and Jumps
Classes and Inheritance
Properties and Fields
Interfaces
Visibility Modifiers
Extensions
Data Classes
Sealed Classes
Generics
Nested Classes
Enum Classes
Objects
Inline Classes
Delegation
Delegated Properties
Functions
Lambdas
Inline Functions
Platform-Specific Declarations
Building with Gradle
Destructuring Declarations
Collections
Ranges
Type Checks and Casts
This expressions
Equality
Operator overloading
Null Safety
Exceptions
Annotations
Reflection
Type-Safe Builders
Type Aliases
Standard Library
kotlin.test
Keywords and Operators
Grammar
Calling Java from Kotlin
Calling Kotlin from Java
Dynamic Type
Calling JavaScript from Kotlin
Calling Kotlin from JavaScript
JavaScript Modules
JavaScript Reflection
JavaScript DCE
Concurrency
Immutability
Kotlin Libraries
Platform Libraries
C Interop
Objective-C and Swift Interop
Gradle Plugin
Debugging
FAQ
Coroutines Guide
Basics
Cancellation and Timeouts
Channels
Composing Suspending Functions
Coroutine Context and Dispatchers
Exception Handling
Select Expression
Shared Mutable State and Concurrency
Documenting Kotlin Code
Using Kapt
Using Gradle
Using Maven
Using Ant
Kotlin and OSGi
Compiler plugins
Coding Conventions
Kotlin Evolution
Stability of different components
Compatibility Guide for Kotlin 1.3
FAQ
Comparison to Java
Getting Started with IntelliJ IDEA
Getting Started with Eclipse
Working with the Command Line Compiler
Working with Build Tools
Koans
Getting Started With Android Development
Kotlin Android Extensions
Android Frameworks
Mixing Java and Kotlin in one project
Kotlin to JavaScript
Getting Started with Gradle
Getting Started with IntelliJ IDEA
Getting Started with Maven
Creating a Kotlin JavaScript library with the Command Line Compiler
Working with Kotlin and JavaScript Modules
Working with JavaScript
Debugging Kotlin in browser
iOS and Android
Multiplatform Library
Basic Kotlin/Native Application
Interop with C Libraries
Mapping Primitive Data Types from C
Mapping Struct and Union Types from C
Mapping Function Pointers from C
Mapping Strings from C
Working with Kotlin/Native Libraries
Targeting Multiple Platforms
Kotlin/Native as a Dynamic Library
Kotlin/Native as an Apple Framework
Gradle for Kotlin/Native
Multiplatform Project: iOS and Android
Asynchronous Programming
Introduction to Kotlin Coroutines on the JVM
Creating Web Applications with Http Servlets
Creating a RESTful Web Service with Spring Boot
Setting up Kotlin on TeamCity
Learning Kotlin with EduTools plugin
Teaching Kotlin with EduTools plugin
Books
More Resources