Avian VS JDK

There's been plenty but they've fallen aside for various reasons.

- GCJ (iirc only pre 1.5-1.6 java support so never with generic versions, not sure if they ever implented JNI but relied on their own so libraries with native bindings had to be manually ported iirc)

- Excelsior JET was a strong option for a long time on desktops up until 2018, main selling point was resistance to decompilation but not sure if they ran afoul of Oracle licensing or couldn't keep up with the accelerated pace of JDK releases in later years.

(The below were options to various degrees for iOS developers)

- Avian VM ( https://readytalk.github.io/avian/ ), opensource and seems to be up but never really saw an uptake or proper debug tooling iirc, seems inactive by now.

- Robo VM was another strong option with strong support for IDE debuggers,etc since it was used by gamedevs and the initial libgdx author was involved in it. Sadly they were sold out to Xamarin shortly before MS bought out Xamarin and then promptly shut down since MS only had interest in Xamarin for their C# iOS/Android toolkits.

- RoboVM forks, luckily RoboVM core was liberally licensed so forks were possible for those working on mobile games with iOS ports even if the tooling wasn't as slick as the official RoboVM project (No idea if any of the open source variants have caught up, it was a bit chaotic initially with many forks).

- Intel had(have?) some AOT compiler for Java that was an option for libgdx developers for a while but RoboVM being more "native" had more eyes and no idea if Intel really had a business case for it's Java things ? (

(Funnily enough, I was actually doing an AOT one during late uni times to write a thesis on game GC's (and hoping to maybe commercialize), then Oracle bought out Sun and I wrote a JS AOT prototype instead. Hearing of Oracle vs Goog it felt sane but Oracle did showcase RoboVM later on so maybe it was silly)

Avian

This comment is not correct. Java uses mixed Latin1/UTF-16 strings. The Latin1 mode is for compact storage of alphanumeric text as the name suggests, but comes at a cost of dispatch to determine the encoding when selecting subsequent handling of indexing and other operations: https://github.com/openjdk/jdk/blob/1ebf2cf639300728ffc02478...

The MAX_PATH limit is annoying legacy backwards compatible stuff, but can be avoided by prefixing paths with \\?\ before passing them into the Windows API.

This is something that languages/runtimes with more effort put into portability already handle for you:

https://github.com/openjdk/jdk/blob/master/src/java.base/win...

If Python doesn't do this it's just because the sort of people who write Python don't care about Windows enough to fix it.

I felt out of the loop, thinking that Zero VM was some kind of new distro for OpenJDK but chasing <https://packages.debian.org/sid/openjdk-22-jre-zero#:~:text=...> to <https://sources.debian.org/src/openjdk-11/11.0.23%2B9-1/debi...> lead me to https://github.com/openjdk/jdk/tree/jdk-22-ga/src/hotspot/cp...

It seems that it's a specific CPU target for the Hotspot JIT for non-mainstream architectures (or for research purposes, as I saw mentioned once)

Completely gutted from the OpenJDK, last I checked. See here for the culprit PR: https://github.com/openjdk/jdk/pull/18688

> Yes, they're changing one aspect of signal handler use to work around this problem. They're not stopping the use of signal handlers in general. Hotspot continues to use signals for efficiency in general. See https://github.com/openjdk/jdk/blob/9059727df135dc90311bd476...

This whole thread is about SIGSEGV, and specifically their SIGSEGV handling. However, catching normal signals is not about efficiency.

Some of their exception handling is still odd: There is no reason for a program that receives SIGILL to ever attempt continuing. But others is fine, like catching SIGFPE to just forward an exception to the calling code.

(Sure, you could construct an argument to say that this is for efficiency if you considered the alternative to be implementing floating point in software so that all exceptions exist in user-space, but hardware floating point is the norm and such alternative would be wholly unreasonable.)

> The wonderful thing about choosing not to care about facts is having whatever opinions you want.

I appreciate the irony of you making such statement, proudly thinking that your opinion equals fact, and therefore any other opinion is not.

This discussion is nothing but subjective opinion vs. subjective opinion. Facts are (hopefully, as I can only speak for myself) inputs to both our opinions, but no opinion about "good" or "bad", "nasty" or not can ever be objective. Objective code quality does not exist.

I remember talking to Brendan about the PreserveFramePointer patch during my first months at Netflix in 2015. As of JDK 21, unfortunately it is no longer a general purpose solution for the JVM, because it prevents a fast path being taken for stack thawing for virtual threads: https://github.com/openjdk/jdk/blob/d32ce65781c1d7815a69ceac...