What is Kotlin?

Learn that Kotlin is a modern JVM-based language.

What is Kotlin?

Kotlin is a modern, statically-typed programming language announced by JetBrains in 2011 and supported today by Google, Android and the Spring ecosystem. Kotlin 2.x is the current long-term release.

Kotlin is a compiled language; source code is turned into JVM bytecode and runs on any JVM (Java Virtual Machine). The same code runs on Windows, Linux and macOS.

It is widely used for Android apps, server services and multiplatform projects.

What can you build with Kotlin?

Kotlin has a wide range of use cases:

Android: a large share of mobile apps are written in Kotlin
Server side: large systems with Spring and Ktor
Multiplatform: shared code with Kotlin Multiplatform
Data science: analysis with Kotlin Notebook

This versatility puts Kotlin at the center of modern ecosystems.

Test yourself

What runs a Kotlin program?
- Only a compiler
- A web browser
- The JVM (Java Virtual Machine)
- The OS kernel
Show answer

The JVM (Java Virtual Machine) — Kotlin bytecode runs on the JVM.
Match the concepts

Kotlin

Programming language
JVM

Runtime
JetBrains

Developer company
Android

Mobile platform
Which can NOT be done with Kotlin?
- Build an Android app
- Write a server service
- Build a multiplatform library
- Write an OS kernel
Show answer

Write an OS kernel — Kernels are typically written in C; Kotlin is not suited for that.

Kotlin is an ___ language

Kotlin is an ____ language.

Show answer

Kotlin is an object-oriented language.

Next lesson: Your first program

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