[izacus]

The non-JVM code used in mentioned context will run in environments where yet another GC fighting the JVM GC isn't desired or have to be a shared library talking to existing JVM code. While you can use Go to build libraries with C calling convention, it's not the most supported use case and it shows in ergonomics. This also includes standard Go types and standard library which don't fit nicely into a model where code needs to talk a lot with JVM world.

It's possible... But it feels like screwing screws with a knife. It's doable, but noone from the language designers, stl designers and library developers are really thinking about that use case.

Rust on the other hand fits very well into the model where it needs to be just a piece of a bigger whole - it's been built that way ("system" programming language) and it doesn't come with GC that will fight with JVM or Binder lifetimes, compatible type system and plenty of libraries that help develop libraries on an embedded platform. When building the language, Rust designers consider this as one of the main use cases of the language and it shows with how much less hassle it is to work with.

The fact that it easily fits into existing C/C++ codebases helps too.