Kotlin is relatively young – only 11 years old – and Android has only had official support for Kotlin for five years. Yet Kotlin is now the go-to language for Android development, and is becoming more popular for desktop and server application development. Kotlin is used by over 60% of Android professional Android developers and it's estimated that 1 million professional software developers use Kotlin as 1 of their 3 primary languages.
Clearly, we are truly in a new age: the Age of Kotlin.
Head over to my latest Guardsquare blogpost to find out why, in the Age of Kotlin, writing ProGuard keep rules requires thinking in terms of Java.