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

19 Mentors

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

7,239 Students

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

84 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

Exercism is a great website where I was able to have some very interesting challenges.

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 Mike Gehard

Mike Gehard My musings on software.

I love writing Kotlin because it has some of the power of Scala without all of the type system complexity. It is a breath of fresh air in the Java ecosystem for those of us that like the JVM but don't like Java.
Avatar of Uzi Landsmann

Uzi Landsmann https://github.com/uzilan

I have been a developer for about 15 years, working daily with Java. I love learning new languages and am trying to learn and adopt a functional programming style.
Avatar of Rajesh Khadka

Rajesh Khadka Twitter

I love to share the knowledge. Kotlin similarities with other modern programming language brought me into it. Currently working on building mathematical foundations for data science.
Avatar of Derk-Jan Karrenbeld

Derk-Jan Karrenbeld https://github.com/SleeplessByte

After being stuck with Java for 8 years, Kotlin was the fresh breath of joy I needed.
Avatar of Peter Nikodem

Peter Nikodem https://github.com/nikodem-peter

Came for Java, stayed for Kotlin. You can't see it in the picture, but I have fully functional arms and legs.
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.
Fun. Challenging. Interesting

Community-sourced Kotlin exercises

These are a few of the 84 exercises on the Kotlin track. You can see all the exercises here.

Armstrong Numbers
easy
algorithms
loops
math
Transpose
easy
lists
loops
maps
strings
ETL
medium
lists
maps
transforming
Nucleotide Count
medium
conditionals
exception handling
integers
maps
parsing
searching
strings
Bank Account
medium
concurrency
exception handling
integers
Difference Of Squares
easy
integers
loops
math
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 Mike Gehard

Mike Gehard

Long time software developer, recovering chemical engineer. I love helping folks along their path because I learn something new every time.
Avatar of Denys M

Denys M

[Mobile] Software engineer and Kotlin enthusiast.
Avatar of Elena Parovyshnaia

Elena Parovyshnaia

Staying with Java since 1.0, currently a Kotlin fan. Experienced in explaining things. Eager learner. Enthusiastic in putting things in order, evolving an infrastructure and processes, easing work for a community.
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!

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