Tom Cools on foojay.io - Friends of OpenJDK

Why We Moved Our Timefold Java Worker Pods from AMD to ARM64

Wed, 08 Jul 2026 15:25:58 +0000

When we investigated unexpected performance variance in our Timefold Solver worker pods on our platform, we traced it to hyperthreading on AMD (x86-64) cloud instances. Switching to ARM (ARM64), where each vCPU maps to a physical core, eliminated the problem and roughly doubled effective throughput per dollar for concurrent solver workloads.

Originally written by Timefold engineers Lars Beckmann, Jenne De Bleser and Lukáš Petrovický

Adapted for foojay by Tom Cools

Foojay Podcast #61: Keep Your Body And Mind Healthy

Mon, 18 Nov 2024 08:03:10 +0000

At Devoxx and JFall, we talked with Georgios Diamantopoulos, Lutske de Leeuw, Tom Cools, Jessica Siewert, and Rijo Sam about staying physically and mentally healthy as software developers.

There are many topics to handle, like the impact of AI on how valuable we feel, how COVID-19 impacted careers, how we work in and with remote teams, how to get to know new colleagues and much more. Yes, there is even a sidestep where we compared the Java and .NET communities.

Foojay Podcast #24: BeJUG, BruJUG, and how Devoxx was born

Mon, 05 Jun 2023 08:21:41 +0000

The Foojay Java User Group World Tour has already brought us to a lot of different countries virtually all over the world.

But for this episode, the host decided to stay at home in Belgium.

The Belgium JUG (BeJUG) started in 1997 and was the birthplace of Devoxx, Devoxx4Kids, and VoxxedDays.

And in our capital Brussels, we’ve been able to join Brussels JUG (BruJUG), since 2010.

So there’s a lot we can talk about to learn more about communities and conferences in Belgium!

Statically Spilling Your (Spring) Beans

Mon, 24 Jan 2022 11:25:13 +0000

UPDATE - To make it abundantly clear:

You should always try to refactor your code so you do not need this approach (something I’ll dive into in a follow up blogpost I’m working on). There may be some edge cases where there truly is no other way but those situations are rare. Always try to refactor!

Using this method can lead to multiple unexpected and hard to debug issues as it does not follow the regular Spring Framework concepts. As such, this approach is considered A VERY BAD IDEA .