Roy van Rijn
@royvanrijn.com
Director of OpenValue Rotterdam, is a @Java_Champions, founder of Rotterdam JUG, public speaking: Java, AI, math, algorithms
How fast can you process 1 BILLION rows of weather data in #Java? 😳 @royvanrijn.com takes on one of the internet's favorite performance challenges, squeezing every last millisecond out of Java through profiling, optimization, and sheer engineering obsession. Watch: youtu.be/pHZF-zJ3Bpg?...
How Fast Can You Parse 1 Billion Rows in Java? – Insane Speed Test • Roy van Rijn • GOTO 2025
YouTube video by GOTO Conferences
youtu.be
For curious developers 🧠 I built "The Anatomy of an LLM", an interactive explainer showing how text becomes tokens, vectors, attention, transformer blocks, and finally generated text. www.royvanrijn.com/anatomy-of-a...
The Anatomy of an LLM | Interactive Visual Guide to How Language Models Work
An interactive visual explainer for developers showing how LLMs work, from tokenization and embeddings to attention, transformers, training, KV cache, and quantization.
royvanrijn.com
Meet Chuck, an AI-powered runtime companion for your Java applications. www.linkedin.com/posts/royvan...
🚀 Introducing Chuck: a brand new Java runtime agent. At OpenValue, we’re always looking for ways to improve developer productivity. Today, we’re excited to introduce our latest innovation: 👉… | Roy ...
🚀 Introducing Chuck: a brand new Java runtime agent. At OpenValue, we’re always looking for ways to improve developer productivity. Today, we’re excited to introduce our latest innovation: 👉 -javaag...
linkedin.com
@dashorst.bsky.social Found wicket "in the wild"... not working though haha. Hey @ns.nl, your portal is broken...
Going to New Zealand in two weeks... and I'm still not convinced platypuses are real, I'm pretty sure it's just beavers-with-strap-on-beaks.
MELBOURNE, Australia, December 4th - #FashionTech Meet-Up, come join! RSVP through the site (free) #Robotics #SmartTextiles #ML #Sensors events.humanitix.com/fashiontech-... Melbourne Dec 1 - 6 Brisbane Dec 6 - 10 Sydney Dec 10 - 13 Canberra Dec 13 - 15 NZ Dec 15 - Jan 5
FashionTech Meetup with special guest Anouk Wipprecht
Anouk Wipprecht is a Dutch designer/engineer working at the cutting edge of FashionTech; where couture meets robotics, AI, and interactive design. Her creations
events.humanitix.com
Really looking forward to see everybody at J-Fall's speakers dinner tonight, who's going to be there?
The em-dash is a clear indicator text was generated by AI. What is the em-dash of generated code?
Next up we’re learning how to use Agentic AI/MCP using Kotlin with David Stibbe
First speaker of the day is @wbauweraerts.bsky.social on moving from fragile to fearless tests. Perfect breakdown on how testing should be used to be able to test and deploy with confidence 💪🏼
There are still some spots available for the next @rotterdamjug.bsky.social meetup: www.meetup.com/rotterdamjug... RSVP now!
📢 Writing Fearless Tests & Agentic AI in Kotlin, Tue, Oct 28, 2025, 5:30 PM | Meetup
**RotterdamJUG** is back with **two** amazing talks: **Wouter Bauweraerts** 🇧🇪 will share how to write tests that truly survive refactoring, while **David Stibbe** 🇳🇱
meetup.com
If you don’t pay for YouTube, you’ll get some unskippable ads… Sooooo if a software conference doesn’t pay their speakers, should they be allowed to sell in-talk ad-segments? 😂 “This talk is made possible by Squarespace/NordVPN/Raid Shadow Legends/Brilliant”
I'm once again looking for awesome speakers and topics for upcoming @rotterdamjug.bsky.social meetup(s). The next one is probably going to be in the week of 27 - 31 October... 👻 🎃 If you're interested, DM me!
☕️ Caffeine is inevitable. Numerous plants across the world evolved producing caffeine independently. To poison bugs, sabotage rivals, and even hack bees’ memories...
Join @royvanrijn.com at #YOW25, where he shows how Java can fly in his talk "Pushing Java to the Limits: Processing a Billion Rows in Under 2 Seconds" MEL 4-5 Dec | BNE 8-9 Dec | SYD 11-12 Dec yowcon.com
Roy, it looks like there is a typo in your resume, it says Scumm Master instead of Scrum Master. ... Nope.
1 billion rows<2s. 🚀 @royvanrijn.com joins #YOW25 & shows how Java can fly in his talk "Pushing Java to the Limits: Processing a Billion Rows in Under 2 Seconds" MEL 4-5 Dec | BNE 8-9 Dec | SYD 11-12 Dec yowcon.com
Imagine travelling to one of the poorest countries in the world, 🇲🇼 Malawi, and being welcomed with more kindness and warmth than you'd expect anywhere. That’s exactly what happened to Rob, a friend of mine. Read his story here: www.100procentmalawi.org/founding
Founding
My journey through East Africa: I had been to Africa several times and each time I was struck by the genuine friendliness and cheerfulness of the people I met. What struck me most was how warm and h...
100procentmalawi.org
Best slogan I could come up with for a software company from Rotterdam 😅 Get your @openvalue.eu Rotterdam laptop sticker at @joyofcoding.bsky.social later this month 👍🏼
Join me tomorrow at @rotterdamjug.bsky.social (Java User Group) with @andresalmiray.com! Andres will talk about deploying to production with confidence and I'll share how to be more productive when working with multicultural teams. www.meetup.com/rotterdamjug...
Deploying with Confidence & Working across Cultures, Tue, Jun 3, 2025, 5:30 PM | Meetup
Join us for an evening of tech insights and real-world stories! **Andres Almiray** will share how to deploy to production with confidence, while **Rijo Sam** explores lesso
meetup.com
Israel has its Iron Dome. America will get a Golden Dome. I propose a similar project for the Netherlands, we can call it… the Thunder Dome.
Last week I tried surimi, didn’t like it, it tastes like crab.
This is by far the best and scariest AI-generated creation I’ve come across. (made with Veo 3)
A shift is happening in our family's € 1000,- investment challenge... I've started to make a comeback, almost back into the green, my partner finally started to drop a little, and kid 1 is in a free fall 😅 📉
