Mattias Karlsson

Jfokus founder, Java Champion, JUG leader, Software Vagabond, Family father, Motorcyclist & Kiva supporter. Check out @jfokus

[Mattias Karlsson @matkar]

@Sharat_Chander @jcon_conference @RichardFichtner Well deserved

[Mattias Karlsson @matkar]

@Sharat_Chander @Oracle Sad news.
I know you are a dog person... for this you have nine lives and will land on your feet. I am sure you will find another place to share your passion.

[Jfokus @Jfokus]

AI agent demos are easy.
Production is hard.
@henrikkniberg is speaking at AI-fokus 2026 about agents beyond the prototype - what works, what breaks, what we’re learning in practice.

May 19 · Stockholm Waterfront
Blind Bird until March 1

https://t.co/kj7TOrLx2k

[Mattias Karlsson @matkar]

@saltnburnem @jbaruch @asm0di0 @Jfokus @halfstackconf A few years back @manicode showed up at @Jfokus in shorts, Hawaii shirt and flip-flops so I dare you to take the challenge!

[Mattias Karlsson @matkar]

@jbaruch @asm0di0 @saltnburnem @Jfokus @halfstackconf We have proper winter this time. Right now -11,6 degrees Celsius

[Mattias Karlsson @matkar]

@jbaruch @saltnburnem @asm0di0 @Jfokus @halfstackconf Nope

[Mattias Karlsson @matkar]

@saltnburnem @jbaruch @Jfokus @halfstackconf There's plenty to do in Stockholm for sure...
https://t.co/Yqjm8GYXpU

[Mattias Karlsson @matkar]

@saltnburnem @jbaruch @asm0di0 @Jfokus @halfstackconf You should visit the Vasa museum and join us for the Sunday speaker activity.

[Jfokus @Jfokus]

🎨 The Renaissance Developer with Kevin Azijn & Adriaan de Jonge.

Spec-driven, AI-powered development that helps Java devs build safer, faster, and better — without vibe coding.
👉 https://t.co/NHlu5rghf4
#Jfokus #DeveloperConference #Java #AI #Architecture #SpecDriven

[Mattias Karlsson @matkar]

@mkheck It's an invitation ;-)

[Mattias Karlsson @matkar]

@Sharat_Chander @venkat_s @RichardFichtner @jeanneboyarsky @CGuntur @frankgreco @eMalaGupta @vincentmayers @zsevarac @mon_beck @therealdanvega @java @JavaOne @Oracle @Oracle_Edu @oracleugs @OracleDevs @OracleAcademy Thanks for having me. Always happy to help out :-)

[Jfokus @Jfokus]

⚙️ Make Your Code Parallel with the Structured Concurrency API with @JosePaumard (Oracle).

Tame the threads and command concurrency like a true Java craftsman ⚡
👉 https://t.co/aT7UhIfQ5S
#Jfokus #DeveloperConference #Java #ProjectLoom #StructuredConcurrency #VirtualThreads #Concurrency

[Mattias Karlsson @matkar]

Merlin!

[Jfokus @Jfokus]

⚙️ More Action, More Overview – From 4K to 1M Threads with Merlin Bögershausen (Moderne Inc).

Harness the power of virtual threads in Java 21+ and run a million tasks without breaking a sweat ⚡
👉 https://t.co/aT7UhIfQ5S
#Jfokus #DeveloperConference #Java #VirtualThreads #Concurrency #Performance

[Mattias Karlsson @matkar]

Sign up for the Spring webinar

[Jfokus @Jfokus]

🚀 Join the next #Jforum meetup hosted by @Advania!
Learn how to build a continuous upgrade culture with Spring Application Advisor 🌸
🗓 Monday 20 October 15:00 - @dashaun, Spring @Broadcom
More info and registration: https://t.co/7uQLRIHXye

#SpringFramework #Java #DevOps #SpringBoot #Developers #Webinar

[Jfokus @Jfokus]

Full house at Oracle Stockholm for Jforum today about Java 25! The Java community is alive in Stockholm ☕ 😎 👏 with
@matkar, David Simms, Antón Seoane Ampudia, Paul Hübner, Joel Sikström and Roberto Castañeda Lozano #community #javaforum #stockholmdev

[Jfokus @Jfokus]

🔥 The new Jfokus 2026 website + 20th anniversary theme drops in just a few days!

Throwback to last year’s keynote ending with Valhalleluja 🎶 — and yes, Nanowar of Steel’s bass player Edoardo Carlesi was on stage and gave a session!

#Jfokus #Valhalleluja

🎥 https://t.co/8sDVqV9D6M
👉 Talk: https://t.co/6yFUO40Vbz

[Jfokus @Jfokus]

Spotlighting more of the rockstar speakers who shaped Jfokus 2025 🙌

We’re now opening the stage for 2026 — will it be you next year?

👉 Submit your talk: https://t.co/TYMxaJ53b6

[Mattias Karlsson @matkar]

Have you submitted yet?

[Jfokus @Jfokus]

Jfokus isn’t just about code. It’s about energy, inspiration, and sharing knowledge 🎸 🔥 ❤️
👉 This year, you can be part of it — not only in the audience, but on stage. Our Call for Speakers 2026 is now open!
Submit here: https://t.co/Y6wB5MQFj9
#Jfokus #CfS #CallforSpeakers #TechConference

[Josh Long @starbuxman]

Excited to speak at JForum tomorrow, in super Stockholm, Sweden, and to see friends old (hi @matkar Neven @laytoun ) and new!

https://t.co/lg6g31yiQa