Rusty Java - Transition the Java Runtime from C/C++ to Rust.

[Julian Waters]

Hi Eric,

That's a very well written document! Thanks for sharing it, it was a
good read. However, unfortunately, virtually everything native in the
Java Runtime is written in C/C++ and transitioning it to Rust would be
a prohibitively enormous undertaking. Java is very dependent on
native, platform specific details, so much so that even just
supporting a different C/C++ compiler on a given operating system (See
https://bugs.openjdk.org/browse/JDK-8288293) is a lot of work, and
even then that not everything in that port works (Notably, awt.dll is
broken completely, and the Java Short Vector Math Library cannot even
be assembled to begin with). Now, having some of the Java Runtime
being written in Rust rather than rewriting the entire codebase might
be acceptable, but I'm not sure everyone would be happy having another
dependency being required by the build system (rustc). One thing I'm
also a little confused about is that the proposal seems to also focus
more on calling Rust code from Java rather than rewriting parts of
Java in Rust? To my knowledge, Panama is working on the ability to
call from any native language, so you might want to look into that too

best regards,
Julian