Kotlin is the “New Java” officially supported by Google from May 2017! It is less verbose (罗唆) than Java which is clumsy with boilerplates (样板), interoperates with Java on JVM, with modern functional programming features, and most importantly,it is Multi-Platform : Java, Android, Javascript, and future versions run as native codes on iOS, MacOS and Linux (Microsoft – work in progress). This eliminates the current headache of having to re-write the same applications for different platforms in different languages.

Google makes Kotlin a first-class language for writing Android apps

https://blog.plan99.net/kotlin-fp-3bf63a17d64a

Kotlin Tutorials:

https://kotlinlang.org/docs/tutorials/

https://developer.android.com/kotlin/get-started.html

Hands-on:

https://try.kotlinlang.org/#/Kotlin%20Koans/Introduction/Hello,%20world!/Task.kt

Two ways to program in Kotlin:

1) Google way: Download Android Studio 3.0 (with Kotlin and Java 8 Support):

https://www.xda-developers.com/you-can-download-the-canary-1-build-of-android-studio-now-supports-kotlin/

2) (A better way): use Jetbrains “Intelli IDEA for kotlin” (bundled with Kotlin)

https://kotlinlang.org/docs/tutorials/getting-started.html

Books:

https://antonioleiva.com/kotlin-android-developers-book/

https://www.amazon.com/gp/aw/s/ref=is_s_ss_i_5_6?k=kotlin+for+android+developers&sprefix=kotlin