[eugeniub]

> Java for Android

Even though OP said they are a Java developer, I would strongly urge going with Kotlin for Android at this point. Kotlin replaced Java as the default language for native Android development in 2017, and new code samples are being written in Kotlin. At the very least, start with Java, and ease your way into Kotlin, since it's 100% interoperable with Java. Aside from being the default Android langauge, Kotlin has many other benefits.

[listenallyall]

Also, Kotlin on the server is better than ever and would likely boost OP's productivity as well.