JavaScript JVM Runs Java

mikejuk writes "The world of software is made slightly crazy because of the huge flexibility within any computer language. Once you have absorbed the idea of a compiler written in the language it compiles, what else is there left to gawp at? But... a Java Virtual Machine JVM written in JavaScript seems like another level of insanity. A lone coder, Artur Ventura, has implemented a large part of the standard JVM using JavaScript and you can check the code out on Github. Notice this isn't a Java to JavaScript translator but a real JVM that runs byte code. This means it could run any language that compiles to byte code." Bonus: on Ventura's website is a set of visual notes from a talk he gave titled "My Language Is Better Than Yours."

Comments

Re:Not A New Concept

[bucky0]

I feel like that sort of bootstrapping is normal. GCC's written in C, afterall.

DOM-Interface for byte code

[maweki]

For years I've been saying that we need a DOM-Interface for byte code in Browsers and everytime I get downvoted. Nice to see people exploring in these directions now.

"we do need DOM-Bindings for Bytecode now more than ever. It would be so great to write code in a language of my choice and compile it to Browser-Bytecode with DOM-Bindings. This would make it possible to deliver more proprietary code without making browser-plugins or something similar."

"What we really need are DOM-Bindings for Bytecode. So you can use every language you want that is capable of compiling to bytecode and send it to a browser. This would make it easier for the developer and bytecode is easier and faster for the browser to execute."

Re:DOM-Interface for byte code

[martin-boundary]

I'd rather have source code than byte code. The web was built on visible code like HTML. Do you think it would have exploded if people couldn't look at the source to figure out how some neat web page was written?

Why now?

[thegarbz]

Legit question from a programming novice: Why are all these discoveries coming up now? Hasn't JavaScript been around for 10+ years now? Is there something that has changed recently that makes people pursue these strange coding goals?

Re:Javaception

[alexhs]

So you could [...] run the browser in itself?

Old news. Try chrome://browser/content/browser.xul in Firefox (doesn't seem to work as a clickable link, though).
See here for more options.

Re:Javaception

[Zortrium]

Warning: shameless self-promotion ahead: I've also written my own JVM interpreter in JavaScript, which supports a substantial amount (perhaps most?) of the standard JVM, including threading, synchronization, reflection, rudimentary I/O, and most of the standard library classes (e.g., HashMap and Random). There's a lot of hackery involved but it's totally doable.

Also, mine runs on Rhino, which is itself written in Java, so it's C (JVM) running Java (Rhino) running JavaScript (JSava, my interpreter) running Java (the user program). How's that for meta-execution?

Re:Not A New Concept

[Just Some Guy]

The JOVIAL J4 compiler was itself written in JOVIAL J4.

Want something really mind-blowing? PyPy is a Python interpreter written in Python. It includes a tracing JIT compiler to optimize hotspots as it runs to get about 5 times faster than the native C Python. I've used it and I still can't quite believe it.