# What Kotlin Is — Kotlin

Source: https://www.skillbyai.com/en/kotlin/f-what

> A pragmatic language with first-class Java interop.

## Statically typed, concise and interoperable

Kotlin is a statically typed, general-purpose language created by **JetBrains** and released as 1.0 in 2016. It compiles to JVM bytecode, to JavaScript and WebAssembly, and to native binaries via Kotlin/Native. Google made it the preferred language for **Android** development in 2019. Kotlin is designed for **100% interoperability with Java**: you can call Java libraries from Kotlin and Kotlin code from Java in the same project. Its main selling points are concise syntax, **null safety in the type system**, functional programming support and **coroutines** for asynchronous code. Kotlin 2.0 introduced the new K2 compiler.

## A concise, safe language for many platforms

Kotlin is a statically typed language from JetBrains that runs on the JVM, Android, the browser and native targets.

![Three ideas: what Kotlin is, setting up a project, and the core syntax.](assets/figures/kotlin/section-1-map.svg) — Figure 1.1 — From source code to JVM, Android and multiplatform targets.

## Hello, Kotlin

A top-level main function needs no class.

```kotlin
// Main.kt
fun main() {
    val language = "Kotlin"
    println("Hello, $language!")
}
```

## A modern renovation of a solid house

Kotlin keeps the foundations of the JVM and its huge library ecosystem, but modernises the rooms you live in every day: less boilerplate, safer nulls and better tools for concurrency.

**Quiz:** Which statement about Kotlin is accurate?

- [ ] It is dynamically typed
- [ ] It only runs on Android
- [x] It interoperates with Java and can use existing Java libraries
- [ ] It requires every function to live inside a class

*Answer:* It interoperates with Java and can use existing Java libraries. Kotlin targets the JVM, Android, JS/Wasm and native, and calls Java directly.