Java or Kotlin?

A language for an Android app is usually one of these two. Kotlin is shorter. Java still stands in older examples.

• A new app usually starts with Kotlin.
• If you know Java, you can read an old project. Kotlin does not erase it.
• Both run on the same phone. One does not throw the other out.
• Turning an HTML page into an APK is not learning this language. Java or Kotlin is needed when you write your own code inside.
• A game often takes another road. An ordinary app is the answer to this question.

If you do not know either, start with Kotlin. If the old code is Java, read that too.