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Johan Janssen

@johanjanssen

Architect at ASML. Conference speaker, JavaOne Rock Star. Chocolateynuget Java packages. InfoQ Java news author.

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21.08.2023
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Latest posts by Johan Janssen @johanjanssen

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Closing the latest chapter in my career. Actively looking to get started with the next one. If you’re looking for a seasoned developer for DevRel, DevOps, and/or engineering roles, let’s chat!

13.01.2026 10:46 👍 31 🔁 14 💬 1 📌 0
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Fray Detects Concurrency Issues in JVM Languages Carnegie Mellon University has introduced Fray, a concurrency testing tool for JVM programs to catch bugs and replay them. Written in Kotlin and based on this research paper, Fray can’t find all concu...

I wrote an article for @infoq.com about Fray which can be used to detect concurrency issues like deadlocks and race conditions in JVM languages: www.infoq.com/news/2025/12...

09.12.2025 10:34 👍 2 🔁 1 💬 0 📌 0

No one with an opinion on the one below? 😃

I basically need to poll something and wait in between...

28.11.2025 10:54 👍 0 🔁 0 💬 0 📌 0

Using #java 25. How would you handle Thread.sleep without blocking? With a virtual thread, CompletableFuture or ...

26.11.2025 12:18 👍 1 🔁 2 💬 0 📌 1

Big thanks to the @oracleace.bsky.social program for organizing everything!

31.10.2025 15:02 👍 0 🔁 0 💬 0 📌 0
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@oracleace.bsky.social extended my ACE Pro status for another years thanks to my contributions to the #Java community. Got some great swag as well. Especially the umbrellas will come in handy with the current Dutch weather 😅🌧.

31.10.2025 15:00 👍 3 🔁 2 💬 2 📌 0

I already made those changes 😃

30.10.2025 08:54 👍 0 🔁 0 💬 0 📌 0

Not yet I only made changes to make sure I could build the application. Will try that next.

30.10.2025 08:11 👍 0 🔁 0 💬 1 📌 0

Tried #springboot 4 RC1, only required a few small changes on our project. Looks like to migration to 4 will be easy 😁.

So make sure to upgrade to #Java 25 and then next month to Spring Boot 4.

Use a tool like dependabot or Renovate to upgrade your dependencies and stay up to date.

29.10.2025 14:29 👍 2 🔁 1 💬 1 📌 0

For some reason the builders weren't working even with the latest version. Adding Lombok as dependency to the Maven compiler fixed it. We now use things like IO instead of System.out and main classes without public static. Relatively simple stuff for now which OpenRewrite did for us.

06.10.2025 15:30 👍 0 🔁 0 💬 0 📌 0

Haha, I have to thank a colleague for adding those spices 😉

06.10.2025 15:28 👍 1 🔁 0 💬 0 📌 0

Upgrading from #java 21 to #java 25 was easy. Only had to fix a Lombok issue. All in all it cost me a couple of hours (less then half a day): some discussion, change build plan, change Maven POM, fix issue, run @openrewrite.github.io so we use the new language features and PR review and merge.

06.10.2025 12:35 👍 17 🔁 5 💬 2 📌 0

That looks awesome!

04.10.2025 13:21 👍 0 🔁 0 💬 0 📌 0

Wow what a view, congratulations!

24.06.2025 07:22 👍 1 🔁 0 💬 0 📌 0

Congratulations, well deserved! Was great using your books at university.

17.05.2025 14:38 👍 1 🔁 0 💬 0 📌 0

Wow awesome, thanks for sharing!

14.05.2025 10:49 👍 2 🔁 0 💬 0 📌 0

Congratulations and welcome!

06.05.2025 09:18 👍 1 🔁 0 💬 0 📌 0
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Gatling documentation Documentation for the Gatling and Gatling Enterprise load testing tools.

Have a look at the documentation if you want to learn more about the tool: docs.gatling.io

15.04.2025 07:14 👍 1 🔁 0 💬 0 📌 0
Ambassador Program | Gatling Become a Gatling Ambassador and connect with passionate advocates to influence product development, share your expertise, and shape the future of performance testing.

I was awarded the Gatling Master title: hubs.ly/Q03hbxR10. I have been using Gatling for many years and wrote/presented about it. It's an awesome tool if you want to do performance testing on, for example, REST based messages, Kafka messages, or Websockets.

15.04.2025 07:12 👍 2 🔁 0 💬 1 📌 0

Did you already walk across the Skywalk bridge in Willingen? If not try, it's a cool and bit scary experience.

04.04.2025 18:45 👍 0 🔁 0 💬 1 📌 0

Family first! I hope he recovers well, take care of your family and yourself!

12.03.2025 04:27 👍 0 🔁 0 💬 0 📌 0

It's awesome that the recording is now published. I had a great tim in Australia at the YOW! Conferences. Hope to go back someday 😀.

11.03.2025 11:36 👍 3 🔁 0 💬 0 📌 0

I bought a Samsung Galaxy A55 last year for way less. Works like a charm.

05.03.2025 12:14 👍 0 🔁 0 💬 1 📌 0

No problem, I maintained them for quite some years 😃.

03.03.2025 20:41 👍 1 🔁 0 💬 0 📌 0
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ajshastri - Overview ajshastri has 23 repositories available. Follow their code on GitHub.

I'm not sure, maybe GitHub is the best place for contact: github.com/ajshastri. Before there was also a link on the Chocolatey package site to contact a maintainer, but I couldn't find it on my phone.

03.03.2025 17:14 👍 0 🔁 0 💬 1 📌 0

I don't think that's possible right now. But I no longer maintain them, so better to ask the current maintainer 🙂. If not, you could create a short wrapper script that installs Temurin with Chocolatey and then sets the env variable.

03.03.2025 16:25 👍 0 🔁 0 💬 1 📌 0
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a van with a license plate that says ' gmc ' on it is parked in front of a building ALT: a van with a license plate that says ' gmc ' on it is parked in front of a building

🤣 I might even need:

22.02.2025 17:24 👍 1 🔁 0 💬 0 📌 0

If everyone would follow the rules, then presentations and life would be quite boring 😄.

22.02.2025 08:20 👍 1 🔁 0 💬 0 📌 0

Only 140 slides, what did you do during the time that was left? 😅😉

21.02.2025 19:51 👍 0 🔁 0 💬 0 📌 0

Yes indeed, personally I rather have some more simple slides with pictures and/or short text then a few slides with a lot of text. But I also enjoy people telling a good and long story with just one slide, or none at all 😀.

21.02.2025 19:51 👍 1 🔁 0 💬 1 📌 0