This may be one of the reasons Google invented Go (language). I wouldn't be surprised to see if future versions of their platforms are Go-lang only. Make Java obsolete
Dart is much much better as a Java replacement and efforts like flutter are really promising for cross language dev - IPC architecture behind it and chrome (Mojo) is how Android should have been implemented, then it doesn't matter what languages you use they are trivial to swap because IDL defined interfaces can be reimplemented transparently and client API can be generated automatically. Instead you are locked in to their JVM
the trade-off here is accepting build slowness & complexity in exchange for escaping the negatives of the default language for your platform.
I think we won't get off this trend until we figure out a bytecode format that balances sandboxing and portability. WASM?
For native apps, I think it's still mainly Java, tho JetBrains is promoting Kotlin as an alternative.
Mozilla resisted dart in the browser and focused heavily on improving javascript which left dart dead in the water.
Weird to me, as it is the best way to ensure every one can do what every they like on your platform (and possible re-use large portions of code on other platforms).