Nashorn And Javascript On The Jvm: Mike Hall Interviews Attila Szegedi | GOTO Conference 2015

Well, we are not even herding them, we just built one. So, Nashorn is German for rhinoceros, so it is a JavaScript runtime on the JVM. There is a bit of a tradition of naming the JavaScript runtimes on the JVM after rhinos, because there was an early O'Reilly book on JavaScript that had a rhino on its cover, so that actually started the big book. Yeah, so I think that that actually started this naming situation, and you know, it allows for some quite nice puns. So yeah, well, the talk was mostly about... I was explaining to people just what are the things that we do to make sure that Nashorn actually runs decently fast on the JVM. There's always... there used to be this stigma of JavaScript runtimes, that it's slow language, and this was mostly dispelled by V8, so Google's V8 has really brought the fast JavaScript runtimes to the market, and we are also doing our best to not be left in dust compared to V8. We're doing a pretty decent job about it. A lot of things that I was actually talking about in my talk are things that we implemented since the original release, so Nashorn had its first release in original Java 8 last March 2014, and since then we did a lot of improvements that you would normally find maybe in a C compiler, so we do a lot of static type inferencing and we do a lot of crazy things like type-specific compilation. We can optimize and deoptimize code on the run, so it turns out that if you want to write a really efficient runtime for your language, you almost need to write half of a half of a VM, really. So the Hotspot VM on the JV M, it already does these things with Java code. It does interpretation of various optimizations, and when it gets it's wrong, then it deoptim izes, reoptimizes, and so on. And it turns out that we wanted to avoid doing these and just rely on the JVM, but the problem is that the language semantics is such, the JavaScript language semantics is sufficiently different from Java, that you can't really just leave it all to the JVM, but we just ended up needing to build a lot of these things on top of it. So it becomes a very sophisticated runtime that can run JavaScript programs on the JVM ever better. I 'm not saying really well, but it's ever improving. It's actually really great because there is a lot of challenges every day when I go to work. There's always the next thing that can still be done to make it more efficient. There is not a particularly great or sexy story behind NASM, because, you know, it's just JavaScript on the JVM, and everything else is really just an implementation detail of how do we want to make it so that it just gets better and faster over time. It's a one interesting thing about NASM is that it was actually the first JavaScript runtime that achieved 100% specification compliance. There is a set of specification tests out there that is openly maintained, that contains some 11,500 tests, and actually NASM was the first JavaScript runtime back in I think October 2012 or so, that we actually managed to implement it so that it passed all of the tests. Now, I'm not a Node developer, but I know that Node and V8s are extremely tightly coupled, but as far as like just JavaScript syntax, you know, as somebody who's working on the compiler, is there anything where you're looking at like, "Oh, there's Node, you know, how can we get Node as a framework running on top of Rhinoceros?

Because like I said, I'm not a Node developer. Yeah, we do actually. We actually have Node version running on NASM. We have a team internally at the company who was writing a version of it, but we are not allowed to call it Node. Oh, yeah, because of copyright and trademarks and stuff like that. Yes, that's right. So, the owners of the Node term have graciously asked us to not use the name, so it actually runs under the name avatar . js. Oracle actually had a server-side technology named avatar, and then the name got expanded and reused. So, avatar. js is, we refer to it as Node API compatible server framework. Oh, okay. So, that kind of gets around that old trademark thing. It's like we're compatible with them, not we are them. So, it's there. It's also available. It's downloadable. You can try it. There's one problem with it that it started out as a great effort, but it started pretty much as a hobby effort by one or two of the developers within the organization. It got adopted, but those guys have since moved on. So, unfortunately, the project itself is pretty dormant, but it was active until a few months ago. It was closely tracking the Node code base, so it's, I mean, again, I cannot say that, yeah, go and use it because it's, at the moment, it might not be actively maintained, but that might change in the future, and by any means, it's still pretty recent, but it also proves just the fact that, yeah, sure, I mean, you can have Node on NAS1. It does work. And, you know, looking at a lot of the, it seems like a lot of the JVM developers cross-communicate whether they're working on JRuby or Cloj ure. I mean, is there been anything that you've looked at from JRuby or the work that Rich Hickey is doing with Clojure that have been pulled into Rhinoceros?

Well, not really much as such. We do, I do talk with Charlie Nutter a lot, so the JRuby guy, and I don't talk that much with Rich Hickey these days , but we run into each other at conferences, but there is this great conference called the JDM Language Summit that Sun Microsystems used to organize and now Oracle organizes every year. It's a really small conference, usually sometime in the summer, at the Oracle's Santa Clara campus, the ex-Sun campus, where language implementers on the JVM get together and it's, and well, exchange knowledge, talk to each other, there's presentations, but it's a very small conference. It's the number of attendees, I don't think it even reaches 100 people, so it's somewhat hard to, hard to get in. It's fairly, highly priced if you, if you can go to the JVM Language Summit. We do talk a lot there. Nashorn, we, we did, we did speak with JRuby folks on few occasions. I think JRuby right now is, is less sophisticated in terms of code generator, typing, optimizations and so on. They do have a new version, JRuby 9000, which is , which is re-taught from the ground up. It has its own internal, separate internal code representation. I think that it will, it will, it will be awesome. It's very, very, very close to, to the release. Yeah, so we talk to each other, there's concepts that, that we talk about, but you know, I wouldn't say that there was a lot in, in actual optimization. Clojure, Clojure also, optimization, I don't think that like language level optimization is high on their list of priorities. They just compile to JVM and then, and then. They don't like to deal with the things, yeah. Well, I just think it's fascinating. I mean, so many developers who are implementation developers, you know, and users of these languages, kind of differentiate themselves. I do JavaScript, I do Clojure, I do this, but the people that are implementing these languages are talking to each other. Yeah, of course. And it's, and if, if the people who are creating languages are talking to each other, it's maybe something that we should think about as end user developers, is that, you know, use JavaScript, use Clojure, use JVM, you know, just, we're all, we're all in this together. It's great. And especially if you are using the dynamic languages and you're deploying on the JVM, you even have a little bit of a, like a common foundation, which is the JVM itself. So all of these people will be using Java libraries. And if you want to, you can even, you can even stitch together a system where if you find, maybe you're writing the majority of your system in, in, in Ruby and you're deploying JRuby, but if you find a particularly nice algorithm implemented in Python, there is nothing really that prevents you from also taking the JITONS jar file and loaded it in and writing a little bit for the integration. And then you can just go from your Ruby code and you can pass some data into your Python algorithm, let it crunch the things, give it back to you. So it's, it's, I, I think that, as time progresses, hopefully kind of a polyglot programming is, is going to be, is, is, is becoming ever more in reality. Yeah, yeah. Just let the, let the virtual machine sort it out. Yeah, of course. That's what they are for.