GraalVM for JDK 21

GraalVM is a hugely under-appreciated piece of technology. A lot of my initial interest came from being able to blend different languages into a single runtime via the polyglot APIs, but the combination of performance, strong sandboxing support, and multi-language support has helped it emerge as a key primitive for anyone wishing to build extensible platforms without sacrificing speed, security, or developer ergonomics.

I&#x27;ve only done one project with GraalVM and I&#x27;ve been pretty happy with it in regards to faster startup time.<p>I was doing stuff in Clojure. Clojure is a great language but it tends to have very slow startup times, even by JVM standards (it&#x27;s not weird for a large Clojure program to take 5-6 seconds to start. Even a &quot;hello world&quot; can take upwards of a second or two). Graal mostly Just Worked with the standalone uberjar produced by Leiningen and created an executable that started in about 3 milliseconds. It was amazing.<p>While the lack of proper reflection support was a little annoying, it actually wasn&#x27;t as horrible with Clojure as you might think; most problems were fixed with basic type hinting, and all but one Clojure library I used (http-kit) worked flawlessly.

We tried to use it to improve AWS lambda startup times but desisted as it was a pain to use it with an existing app. It required too many tweaks as there are waay too many things that rely on reflection :(<p>Things that broke include: JSON (de)serialization using Jackson, validations using hibernate, validator, AWS SDK, and even simpler libs like picocli...<p>It could be quite useful for a set of simpler apps though

From 5 years ago, but still fascinating: Ten Things You Can Do With GraalVM by Chris Seaton<p><a href="https:&#x2F;&#x2F;gist.github.com&#x2F;chrisseaton&#x2F;535e0e80ea19803d5529c623c6beb921" rel="nofollow noreferrer">https:&#x2F;&#x2F;gist.github.com&#x2F;chrisseaton&#x2F;535e0e80ea19803d5529c623...</a>

Seems like every time I try to use Graal - there&#x27;s some dependency in my project that doesn&#x27;t like it.

The linked sibling post on &quot;New Truffle and GraalVM Languages release&quot; feels rather exciting too <a href="https:&#x2F;&#x2F;medium.com&#x2F;graalvm&#x2F;new-truffle-and-graalvm-languages-release-1e5c8cdaaff" rel="nofollow noreferrer">https:&#x2F;&#x2F;medium.com&#x2F;graalvm&#x2F;new-truffle-and-graalvm-languages...</a><p>Specifically:<p>&gt; GraalVM language runtimes (for JavaScript, Python, Ruby, Java on Truffle, WebAssembly, and LLVM) can now be [...] installed as Maven&#x2F;Gradle dependencies [...] which will work for GraalVM JDK and any other compatible JDK<p>Polyglot experimentation just got a whole lot easier! Kudos to everyone involved in pushing the JVM ecosystem forwards.

I just wish the compile times weren&#x27;t so painfully slow. It makes it really difficult to work with.

What’s the latest on Truffle&#x2F;Ruby supporting Rails?<p>Wouldn’t this provide massive gains for the Rails ecosystem once delivered?<p>(And with the GraalVM licenses changes to be more favorable&#x2F;permission, I have to imagine there would be significant adoption)

I am more interested in this proposal<p><a href="https:&#x2F;&#x2F;openjdk.org&#x2F;jeps&#x2F;8313278" rel="nofollow noreferrer">https:&#x2F;&#x2F;openjdk.org&#x2F;jeps&#x2F;8313278</a><p>It is &quot;Ahead of Time Compilation for the Java Virtual Machine&quot;. The proposal details of using AOT code at startup and then JIT taking over. So you get best of both worlds with fast application launch and then throughput once things are warmed up.<p>Graal is cool, but it will not be as throughput performant compared to JIT. Only for fast startup, serverless or low memory environments.

Congrats to the GraalVM team on all their hard work

I think the biggest improvement in GraalVM 21 is profile-guided optimizations (PGO) in both aarch64 and amd64.<p>This means you can take full advantage of ARM cloud services like AWS Graviton (sp?) services for lower cost.<p>Also, looks like the Java Vector API (JEP338) has been optimized.<p>So, same code on your Raspberry Pi and AWS Graviton, cool.

Lots of comments about issues with dependencies and Graal. I suggest looking into Quarkus. Have had great success with and mandrel (a patched version of Graal for Quarkus). Quarkus focuses on creating Web APIs so wont cover it all but if thats what you want to do its great and builds native images quite easily.

I&#x27;ve slowly been keeping myself updated regarding GraalVM, I think Oracle is on to something here.

I use Graal Native to AOT compile my JavaFX applications. It works surprisingly well.

it’s time to do a barrel roll

Warning: Graal is owned by a law-firm called Oracle (that happens to employ some programmers too).