For years, Java was the one official language for Android development. While other options were available through alternative tools like Unity or Xamarin, Java with the Android SDK was still the clear choice for those wanting to learn Android development the “proper” way. Then came Kotlin for Android.
As of 7 May 2019, Kotlin has been the official “preferred” language for Android development according to Google. It has been available as a built-in feature of Android Studio and an official language for Android for longer than