To date, Kotlin has received the most popularity in the Android development community. Kotlin starting gaining traction for Android development in 2015, but it was 2017 when Kotlin really came to the forefront. At Google IO 2017, Google announced first-class support for the Kotlin programming language. It was to sit alongside Java and C++ as officially supported languages for the platform and this marked the beginning of the large-scale adoption of the language.
When Android Studio 3.0 was released in October of 2017, there was no longer a major blocker to adopting the language in established projects. Teams that had been concerned about prerelease versions of plugins or IDEs could now try the language on stable tooling with the full, long-term support of Google. This allowed teams and organizations to adopt the language with much more confidence and began the surge in Kotlin's popularity that we see today.
IntelliJ and Android Studio both make it incredibly easy to integrate Kotlin with existing Android projects, or to start new projects that are 100% Kotlin. Additionally, Google continues to invest in Kotlin with improved tooling and the Core-KTX Jetpack library, which makes building Android applications with Kotlin even more enjoyable.
Chapter 13, Kotlin on Android, will dive deeper into the usage of Kotlin for Android application development.