Kotlin

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Kotlin is a pragmatic programming language for JVM and Android that combines OO and functional features and is focused on interoperability, safety, clarity and tooling support.
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Track mentors

14 Mentors

Our mentors are friendly, experienced Kotlin developers who will help teach you new techniques and tricks.
Track students

2,490 Students

Join thousands of students who have enjoyed learning and improving their skills by taking this track.
Track exercises

63 Exercises

Hundreds of hours have gone into making these exercises fun, useful, and challenging to help you enjoy learning.

About Kotlin

fun getGreeting(): String {
    return "Hello, World!"
}

Kotlin was designed and developed by JetBrains, the company behind IntelliJ. It is a language that runs on the JVM which can target versions 6+ (including the Android platform). JetBrains wanted to use a statically typed language which can remove Java boilerplate code, provide modern functional paradigms, and had seamless two-way Java interoperability with their existing codebase. The JVM already had alternate languages like Groovy and Scala but neither fit the bill with their desired criteria, so they built Kotlin.

Kotlin syntax is similar to Scala and Swift but pulls in the best-of-breed features from other languages such as C# and Groovy. Kotlin took a pragmatic approach at features included in the language by only providing functionality that has been proven to be useful for developers. With this decision they implemented a subset of features of Scala with the intent that it will provide more maintainable code with an easier learning curve for developers looking for a "better Java".

JetBrains has a dedicated team of developers working on Kotlin with the codebase available on Github.

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Exercism is a great website

The reviews are incredibly helpful because they help me see things that I missed, learn about new ways and sometimes interesting discussions that can add a fun twist to maybe a simple problem.

Relaxed. Encouraging. Supportive.

Meet the Kotlin Track mentors

Once you join the Kotlin language track, you will receive support and feedback from our team of mentors. Here are the bios of a few of the mentors of this track.

Avatar of Alex Ahern

Alex Ahern https://github.com/aahern

I work as an Android developer on one of the oldest apps in the UK Play Store. We have been using Kotlin as our primary language for around a year now, and I'd like to help others develop their skills while at the same time developing my own.
Avatar of Gurpreet Singh

Gurpreet Singh Website

I am an Android Developer based out of New Delhi, and have been working with Kotlin for over a year. I'm particularly interested in Functional & Reactive programming paradigm and like to share my knowledge and learn from others.
Avatar of Andrej

Andrej https://github.com/andrej-dyck

I love Kotlin for its simplicity and expressiveness. I've programmed in Kotlin professionally, and for me its the language that makes programming `fun` again ;).
Avatar of Sinuhe Jaime

Sinuhe Jaime https://github.com/sierisimo

I'm a geek doing a lot of things, including Kotlin. I've using the language for 3 years now but still learning everyday
Avatar of Robin Roschlau

Robin Roschlau Twitter

I've been slightly addicted to Kotlin ever since I first used it, coming from Java a few years ago, so much so that I started a Kotlin User Group in my area and am regularly holding talks about it.
Avatar of Jacob Andersen

Jacob Andersen https://github.com/simpleauthority

I've been using Kotlin for smaller projects for about a year. I find its simplicity and expressive nature very refreshing. I'm ready to help you bring your Kotlin skills to the next level.
Fun. Challenging. Interesting

Community-sourced Kotlin exercises

These are a few of the 63 exercises on the Kotlin track. You can see all the exercises here.

Difference Of Squares
easy
integers
loops
math
Pangram
easy
pattern matching
regular expressions
strings
Series
medium
conditionals
lists
loops
strings
type conversion
Sublist
medium
enumeration
generics
lists
loops
searching
ETL
medium
lists
maps
transforming
Passionate. Knowledgeable. Creative.

Meet the Kotlin Track maintainers

The Kotlin Maintainers are the brains behind the Kotlin Track. They spend their spare time creating interesting and challenging exercises that we can all learn from. We are incredibly grateful for their hard work. Here are the bios of a few of the maintainers of this track.

Avatar of Sam Warner

Sam Warner

I am a software developer and consultant working for Black Pepper Software, a software company based in Leamington Spa, England. I'm a recent Computer Science graduate from the University of Warwick, and love all things to do with computers!

Get started with the Kotlin track. As with everything on Exercism, it's 100% free!

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