[m_ke]

From what I remember Kotlin came to Android before Google embraced Jetbrains and Android Studio.

[endorphone]

May 2013 - https://blog.jetbrains.com/blog/2013/05/15/intellij-idea-is-...

May 2017 - https://www.theverge.com/2017/5/17/15654988/google-jet-brain...

You could use Kotlin for years before Google officially endorsed it...given that Android Studio is made by JetBrains and they made it trivial to use. JetBrains did 100% of the heavy lifting, and Google just conceded eventually.