Nim doesn't have a JVM backend, but it does C, C++, Objective-C, JavaScript, LLVM (not yet ready for prime time, but almost there), iOS, Android, and more.

Lisps have been doing this since forever (including the now defunct LinJ for Java which compiled into code that was very often mistaken for hand-written Java).

Hell, Emscripten takes everything LLVMable and gives it that ability.

> This is unprecedented.

Only for sufficiently narrow "this".