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Comment by gravypod | Hacker News Reader

The benefits of the JVM still stand out to me personally. Run anywhere, generate machine code at run time most place, world class optimizing compiler, battle tested & ready to deploy, integration with existing code base for gradual rewrites, etc.

Wasm is a good idea but it's going to need to reimplement a lot of existing code (optimizing + jit).

Doable and maybe it will convince people to do what has been a great idea first widely deployed by Java: compiled language in an abstract machine.

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The JVM had many chances to realize that goal. Java applets, J2ME, etc. I’m not sure which particular issue really kept it from keeping mindshare. I don’t think the virtual machine itself was ever really the problem.

Still, since the Java platform didn’t capture this use case of a general purpose abstract machine, it makes a whole lot of sense to develop something like WASM. It’s a much more neutral platform to build on.

In particular we actually don’t need to go through all of the things Java went through; we have a wealth of knowledge about what things work and what things don’t work so well. Yes, its a new JIT, but not that new: from my understanding typically the JavaScript JIT machinery is reused for the WASM JIT in browsers.

> I’m not sure which particular issue really kept it from keeping mindshare.

The fact that it was bundled as a browser plugin, mostly.

java browser plugins have always been poorly designed and implemented

in v8 at least, we just plugged wasm into v8's existing jit. no need to make a new one from scratch.

>Wasm is a good idea but it's going to need to reimplement a lot of existing code (optimizing + jit).

Where the hell did you get that idea? WASM can be used as just another frontend for javascript JIT engines like V8 or SpiderMonkey.

If JavaScript JITs are anything like Java JITs then it might be that most of the performance-improving optimizations are based on optimizations of how Java/JavaScript operate and recognizing specific patterns that can be replaced with simpler instructions to improve performance. The JavaScript JITs help with the machine code generation but not necessarily with other higher-level optimizations.

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