Kotlin

Definition

Kotlin is a statically typed, cross-platform programming language developed by Jetbrains

  • License: Apache 2.0
  • Runtime: JVM, JavaScript, Native (LLVM)
  • Creator: JetBrains (led by Dmitry Jemerov and Roman Elizarov)
  • First released: 2011; officially adopted as Android’s primary language by Google in 2017

Language Features

  • Null safety: Built-in null-safety (nullable types: String?, non-nullable: String)
  • Extension functions: Add methods to existing classes without inheritance
  • Coroutines: Lightweight concurrency without callback hell
  • Data classes: Auto-generated equals(), hashCode(), toString(), copy()
  • Smart casts: Automatic type casting after is checks
  • Interoperability: 100% compatible with Java, inline classes | | Kotlin 1.2 | 2017 | Kotlin/Native (experimental) | | Kotlin 1.3 | 2018 | Coroutines (stable), inline-classes | | Kotlin 1.5 | 2020 | Sealed interfaces, context receivers | | Kotlin 1.6 | 2021 | inline-classes (value classes), inline-classes | | Kotlin 1.9 | 2022 | inline-classes (reified type parameters) | | Kotlin 2.0 | 2024 | Context receivers, inline-classes (reified), improved compiler |

Android Ecosystem

Component Description
Android SDK Official Android development
Jetpack Compose Modern declarative UI toolkit
Ktor Asynchronous web framework
Kotlin Multiplatform Shared code across Android, iOS, desktop, web

Use Cases

  • Android application development (primary language)
  • Server-side development (Ktor, Spring Boot)
  • Cross-platform mobile (Kotlin Multiplatform)
  • Desktop applications (Compose for Desktop)
  • Web development (Kotlin/JS)