I've successfully used RoboVM to ship native linux binaries from jvm bytecode, in addition to the headlining cross-platform-mobile features. It's fantastic. It worked pretty much out-of-box with a few commands from the Getting Started page.

And as for performance: startup time is impressive: an order of magnitude faster than launching a jar in the jvm, such that you can actually use it in the middle of other shell scripts without blinking. Once it's been running for a while, it's hard to beat the kind of optimizations a JIT compiler can do, but RoboVM is still approximately as fast as java (I think the mailing list handwaves this to about 2x slower; still a couple hundred times faster than most interpreted languages, so I'm pretty okay with this).

RoboVM uses the Boehm GC, which is mature, effective, and (of critical note to me) a heap-compacting garbage collector... which means you can confidently use it even for applications with days or months of contiguous uptime.

I've thrown wicked strange bytecode at RoboVM. It copes fine; I was impressed. (After some time working in golang gave me a great appreciation for the semantic style of goroutines, I've been trying to bring them everywhere. I made some custom bytecode with code derived from the Apache JavaFlow library to try to break RoboVM, and it didn't even blink; I'm now using it with http://paralleluniverse.co/quasar/ very happily.)

And did I mention how pleasant it is to ship statically linked native executables?