Johan Vos

Johan Vos

@johanvos.bsky.social

Java Champion, Gluon and LodgON. co-lead OpenJFX, lead OpenJDK-Mobile . Java for science, Quantum Computing. PhD

870 followers75 following319 posts

If you quickly want to build a private app without learning anything, all good to use stochastic-based brute force tools. But if you need or want to understand, *really understand* what you deliver, I highly recommend reading docs/blogs, watching presentations, talking and learning.

Johan Vos reposted

I recently looked deeper in the Java Vector API, and I'm seeing performance improvements when using it for quantum computing (in Strange, github.com/redfx-quantu...). I hope to merge a patch in the near future, and it might make a good talk for the JavaChampions Conference. #java #quantumcomputing

github.comGitHub - redfx-quantum/strange: Quantum Computing API for JavaQuantum Computing API for Java. Contribute to redfx-quantum/strange development by creating an account on GitHub.

I'm very excited about the Java track at Devoxx Belgium (devoxx.be). This is real content, from human core developers who *understand* what they are doing. It helps understanding how and why Java works the way it does. If you want improve your developer skills, I recommend joining. #java

devoxx.beDevoxx Belgium – A Developer Community EventJoin 20,000+ developers at Devoxx Belgium. Explore AI Agents, Java 25, and cutting-edge tech. Annual conference in Antwerp with talks, demos, and networking.

The AI narrative is mainly about marketing. When there was a bug in the Java sandbox in the browser 30 years ago, it would be called "a bug in the Java sandbox". Today, it would be framed as "OMG, Duke went rogue and escaped from its environment!".

The original Java developers had the ethics to at least try to fix the sandbox instead of shifting the problem to a marketing department that changed it into an opportunity. #Java #ethics

Johan Vos reposted

The deeper I dive in the details of NetBeans, the more impressed I am with the codebase and build system. The original parts of NB are pretty old, and that shows, but not in a negative way. New code lives in the same repository. (1/2)

The whole thing is very well maintained and combines the charms of old JDK with up-to-date code patterns. I compare it with a great combination of well-preserved historic buildings and modern architecture. (2/2)

Glad to see the amount of posts with this message (code never was the problem; writing is easy, maintaining is hard) is increasing. The message I keep adding is: coding is cheap, understanding is what makes you valuable.

Erik Nygren@erik.nygren.org

Building software is the easy part. Maintaining it is the hard part. This has always been a problem going back to the myth of "I can code that up in a weekend".

Johan Vos reposted

“Nobody is losing control of an emerging intelligence. They’re redirecting their own agency to the thing they are building.” It’s a myth, a self-affirming form of sense making: they take the action to build it, but insist on describing it as if they are passive witnesses to an inevitable force.

mail.cyberneticforests.comThe System From NowhereWhen Accountability Goes Rogue 💡I recently spoke with Dr. Zena Assaad for her podcast, Responsible Bytes. Video is above, below is an essay adapted from the conversation. "The system from nowhere" i...

I see headlines like "AI writes the code, humans can spend more time thinking about decisions". IMO writing code never was a problem. On the contrary, while writing code, developers gained a better understanding. If you stop writing code, you lose insights needed for decisions. Understanding is key.

This is huge. Very excited it will be (as a preview feature) in JDK 28. Congrats to all contributors.

Mark Reinhold@mreinhold.org

The first part of OpenJDK’s Project Valhalla, JEP 401 (Value Objects), has been integrated into JDK 28 as a preview feature and is now available in the early-access builds. More information: openjdk.org/projects/val... #JDK28 #OpenJDK #Java

Looking for input/feedback from Java developers on 2 different topics: 1. Is there interest in a JavaFX workshop/conference/training in Belgium? 2. Is there interest in a gathering with fellow Java developers working on scientific topics (writing java code, not only using 3th party code) #java

Important: we (Gluon) provide all those builds (with CPU patches) for free. It's a fair amount of work to do this. Please support us by: 1. buy LTS subscriptions (even if you can download them for free) 2. contact us for T&M work 3. spread this news Thanks for keeping JavaFX a community effort.

Imho, the role of scientists is very important. Scientific evidence is increasingly ignored by the public and politicians if it doesn't fit agendas (e.g. ignoring climate scientists). But laws of nature don't change because people don't like them. Time to show more respect for scientists and nature.

Johan Vos reposted

The last Belgian #Java User Group before the summer stop is in the books! Thank you again to @oniryx.be for hosting us every year in June since we started! A big massive thank you to @glycin.bsky.social and @ted.dev for presenting #spring and #eventsourcing See you all after summer! ☀️

My advice to junior developers wondering if they should write code: yes, please do! Write code, use whatever assist tools you want to, but most of all: learn! Make sure to understand every single line you write. When you fix an issue, understand why it failed, and why it works with your fix. (1/2)

A growth in understanding is an incredible valuable asset. I don't care at all how "good" devs are with "prompts". I want them to understand what they do. (2/2)

Absolutely agree. As an OSS dev myself, I know how frustrating this is. I believe one of the problems is that the concept "open source" has been abused by big companies because it sounds friendly, and they make lots of $$ with it, creating different user expectations.

Dan Allen@mojavelinux.com

So many still don't understand the open source contract. I don't develop code for your needs. I develop code for my needs and share it with you to use however you like (in accordance with the license). Nothing says I have to continue working on it or accept contributions. I might, but I might not.

I've spent most of today (and the past few days) on JavaFX 17/21/25 LTS. It's a lot of work, but almost a pleasure because the tools/procedures are so clear. Skara is extremely helpful with backports. And it's deterministic. JavaFX is very well maintained. #openjfx #openjdk

Often, the real problem in software development seems to me comparable to fixing a system with 5 equations and 6 unknowns, or 6 equations and 5 unknowns. Once you have an equal amount of independent equations and unknowns, consider it done (writing the code is not the problem).

Years ago, I created RedFX, a Quantum Computer simulator in #Java (github.com/redfx-quantu...) and wrote a book about QC (with Java) (www.manning.com/books/quantu...) . My main goal was to understand QC, and writing (code/book) helped a lot. Now I want to move forward, and do more useful things.

github.comGitHub - redfx-quantum/strange: Quantum Computing API for JavaQuantum Computing API for Java. Contribute to redfx-quantum/strange development by creating an account on GitHub.

About the useful things I want to do with Strange: I want to leverage the very latest #OpenJDK features, make it much faster and have a better API. And I want to experiment with more qc algorithms. #quantumcomputing

Most recent Quantum Computing headlines focus on "breaking encryption" (negative framing). I wish there was more attention for the positive things QC can do, e.g. in drug discovery, using VQE. #quantumcomputing

Enjoy the latest and safest releases of JavaFX! And if you want to help us building/distributing these releases, consider our LTS support at gluonhq.com/lts

Excellent writing from Markus. "In real Java systems, the hard part was never mostly typing. The hard part is understanding what the system is allowed to do, what it must never do..." -> I absolutely agree.

Markus Eisele@myfear.com

I use AI every day, and I’m less convinced the real gain is productivity. For senior Java devs, a lot of the work just moved: less typing, more review, more judgment, more mental load. buff.ly/fyU31Vx

Glad to see the Headless JavaFX Platform is being used. It really makes automated UI tests on CI much easier.

Frank Delporte@frankdelporte.be

#Lottie4J had a unit test I marked "can not run on CI, because it requires a display." #JavaFX 26 fixed that with a built-in headless platform. Full story of how it helped me to run visual comparison tests on GitHub Actions: webtechie.be/post/2026-04... #Java #JavaFX #Lottie4J

Johan Vos reposted

Excellent read. A sufficiently detailed spec is not far from code. I wouldn't be surprised to see a formal grammar for specs emerge, at which point we'll just have invented a higher level programming language or reinvented MDA. And then we'll just need a compiler, not an LLM.

gabby@fullmoon.id

New blog post: "A sufficiently detailed spec is code" I wrote this because I was tired of people claiming that the future of agentic coding is thoughtful specification work. As I show in the post, the reality devolves into slop pseudocode haskellforall.com/2026/03/a-su...

Gluon continues to lead the OpenJFX project. Here is JavaFX 26.

Gluon@gluonhq.bsky.social

JavaFX 26 is available! Featuring the new macOS Metal pipeline and a Headless platform prototype. Read all about it here: gluonhq.com/javafx-26-is... #Java #JavaFX

Johan Vos reposted

Just released CameraApp on #windows and #linux appstores! Check out this project which resurrects my old passion of doing work with #JavaCV and #JavaFX 🚀 github.com/rladstaetter... Download Binaries here github.com/rladstaetter... #snap #rpm #deb #msi

github.comGitHub - rladstaetter/CameraApp: Display a videostream from your webcam with JavaFX and JavaCVDisplay a videostream from your webcam with JavaFX and JavaCV - rladstaetter/CameraApp

Johan Vos reposted

We’ve all been there. You’re working on a JavaFX application, and you hit that wall. You search the forums. You check Stack Overflow. You spend days tweaking code, hoping for a breakthrough. There is a faster way! Read more: gluonhq.com/why-spend-a-...

gluonhq.comWhy spend a week on a bug that we can fix in an hour? - GluonWe’ve all been there. You’re working on a JavaFX application, and you hit that wall. Maybe it’s a strange rendering glitch on a specific OS, a memory leak you can’t pin down, or a performance bottlene...