The caveat to mention here is that this is with the standard IO interface. If you use Core.println instead of println you get something substantially smaller. A limitation of v1.12 is that the handling of IO is not that great, and this is something that IIUC is being addressed in the v1.13 updates.
I just tried compiling using Core.println and still got a 92MB build directory.
If you want to LOL even more, see Rust or Go with a full static linked binary without using something like UPX.
I have, and what's worse, those ecosystems full on encourage static linking as a panacea, at least Rust used to.