Kotlin
Andrey Breslav
Story
Kotlin was developed by JetBrains, the Czech software development company best known for creating popular integrated development environments like IntelliJ IDEA, PyCharm, WebStorm, and Android Studio. The project was initiated in July 2010 when JetBrains was looking for a more productive alternative to Java for their own development needs. JetBrains had been using Java for their products but found it increasingly verbose and lacking modern language features that were becoming standard in newer languages. However, they couldn't simply switch to another JVM language like Scala because they needed something that would compile as fast as Java, have excellent IDE support, and be easy for their large team of Java developers to adopt. Finding no existing language that met all their requirements, JetBrains decided to create their own. The language was named after Kotlin Island (Котлин), a small island near St. Petersburg, Russia, where some of the JetBrains team members were located, following the tradition of naming languages after islands (like Java and Ceylon). The project was led by Andrey Breslav, who became the lead language designer, with a team of experienced language developers and compiler engineers. From the beginning, Kotlin was designed with pragmatism in mind: it needed to solve real problems that developers faced daily, compile quickly, integrate seamlessly with existing Java code, and be easy to learn for Java developers. JetBrains open-sourced Kotlin in 2011 under the Apache 2 license, making it freely available and encouraging community participation. The early years of Kotlin development focused on refining the language design, building a robust compiler, and creating excellent tooling support in IntelliJ IDEA. JetBrains used Kotlin internally for their own products, which provided valuable real-world feedback and helped identify issues before the language reached a wider audience. The first stable release, Kotlin 1.0, was announced in February 2016 after years of development and refinement. This release marked Kotlin as production-ready and came with JetBrains' commitment to backward compatibility. The timing was fortuitous, as Android developers were increasingly frustrated with Java's limitations and Oracle's legal disputes with Google over Java APIs. Kotlin offered a modern alternative that worked seamlessly with existing Android development tools and libraries. The language began gaining traction in the Android community, with developers appreciating its conciseness, null safety, and modern features. The turning point came at Google I/O 2017 when Google announced official first-class support for Kotlin on Android, placing it alongside Java as a supported language. This announcement was met with tremendous enthusiasm from the Android developer community, and Kotlin adoption accelerated rapidly. Google's endorsement validated Kotlin's design and gave developers confidence to adopt it for production applications. Major companies including Pinterest, Uber, Netflix, Trello, and Coursera announced they were using Kotlin for their Android apps. In May 2019, at Google I/O, Google went further and announced that Kotlin was now the preferred language for Android app development, with new Android APIs and features being designed with Kotlin in mind. This was a historic moment, as it marked the first time Google had officially preferred a language other than Java for Android. Google also announced that over 50% of professional Android developers were using Kotlin, demonstrating its rapid adoption. JetBrains continued to invest heavily in Kotlin's development, expanding its capabilities beyond the JVM. Kotlin/Native, announced in 2017, allows compiling Kotlin directly to native binaries without a virtual machine, enabling Kotlin to run on iOS, embedded systems, and other platforms. Kotlin/JS enables compiling Kotlin to JavaScript for web development. These efforts culminated in Kotlin Multiplatform, a technology that allows sharing code between different platforms while still accessing platform-specific APIs when needed. This has made Kotlin attractive for companies wanting to share business logic between Android and iOS apps while maintaining native user interfaces. Kotlin has also found success in server-side development, with frameworks like Ktor (created by JetBrains) and Spring Boot providing excellent support for building backend services. The language's coroutines make it particularly well-suited for building scalable, asynchronous server applications. Major companies including Amazon, VMware, and Atlassian use Kotlin for their backend services. The language has evolved steadily with regular releases, adding features like inline classes for performance optimization, contracts for better static analysis, sealed interfaces, context receivers, and continuous improvements to the type system and compiler. Each release has maintained backward compatibility, ensuring that existing code continues to work. Kotlin's success has been remarkable, growing from a JetBrains internal project to one of the most popular programming languages in just over a decade. The language has won numerous awards and consistently ranks high in developer satisfaction surveys. Its success demonstrates that there was indeed room for a better JVM language that could coexist with Java while providing a more modern and productive development experience. JetBrains continues to lead Kotlin's development with input from Google and the broader community, ensuring the language evolves to meet the needs of modern software development while maintaining its core principles of pragmatism, safety, and interoperability.
Description
Kotlin is a modern, statically typed, cross-platform programming language developed by JetBrains that runs primarily on the Java Virtual Machine (JVM) and is fully interoperable with Java, while also supporting compilation to JavaScript and native code for various platforms. Introduced in 2011 and reaching its first stable release in 2016, Kotlin was designed to be a more concise, expressive, safe, and pragmatic alternative to Java while maintaining 100% interoperability with existing Java code, libraries, and frameworks. Google announced official first-class support for Kotlin on Android at Google I/O 2017, and in 2019 declared it the preferred language for Android app development, cementing its position as a major programming language. Kotlin addresses many of Java's pain points and verbosity while preserving the strengths of the JVM ecosystem. The language features built-in null safety that eliminates the billion-dollar mistake of null pointer exceptions by distinguishing between nullable and non-nullable types at the language level, extension functions that allow adding functionality to existing classes without inheritance, data classes that automatically generate boilerplate code for value objects, sealed classes for representing restricted class hierarchies, coroutines as a first-class language feature for writing asynchronous, non-blocking code in a sequential style, and powerful functional programming capabilities including higher-order functions, lambdas, and immutability support. Kotlin's syntax is clean and concise, often requiring significantly less code than equivalent Java while remaining highly readable. The language supports multiple programming paradigms including object-oriented, functional, and procedural programming, giving developers flexibility in their approach. Kotlin includes smart casts that automatically cast types after null checks or type checks, eliminating redundant casting, operator overloading for creating intuitive APIs, delegation as a first-class language feature, inline functions for performance optimization, and a sophisticated type system with generics, variance annotations, and type inference. The language provides excellent tooling through IntelliJ IDEA and Android Studio, with features like intelligent code completion, refactoring tools, and seamless Java interoperability. Kotlin Multiplatform allows sharing code between different platforms including JVM, Android, iOS, JavaScript, and native applications, enabling developers to write business logic once and use it everywhere while still accessing platform-specific APIs when needed. The language has a comprehensive standard library that extends Java's standard library with useful functions and utilities, making common tasks easier and more expressive. Kotlin is widely used for Android development, server-side applications, web development, desktop applications, and increasingly for multiplatform mobile development. The language has gained rapid adoption in the industry, with major companies migrating their Android apps and backend services to Kotlin, citing improved developer productivity, fewer bugs, and better code maintainability.
Use Cases
Google™:
Android app development and backend services.
Netflix™:
Android applications and backend microservices.
Uber™:
Android mobile applications and backend services.
Pinterest™:
Android app development and server-side applications.