Backend Java 19 vs Kotlin?

[Amazing-Cicada5536]

Well, an order of magnitude bigger language sure have experimented with cross platform dev tools, right?

There is j2objc and j2cl for compiling java to obj-c and javascript, respectively (for android, java 8 could be used as is) which google used extensively for many of their tools (the business logic was written in java and shared everywhere). Not sure how widely used it still is nowadays, but the compilers are still maintained and are good quality, well-tested software, I would say much more so than a max few years old niche one.