René Schwietzke

CEO and co-founder of Xceptance. René has served as Xceptance’s Managing Director since 2004 including the continuous evaluation and development of test tools and services. He holds a Master’s degree in Computer Science from Brandenburg University of Technology, Germany.

He has been working with Java since version 1.0. While working with and for two ecommerce and one quality assurance company, he gained plenty of insides into Java, performance tuning, and performance measurements that includes but is not limited to JIT, GC, and the JMM.

René regularly gives talks and training about programming in Java, GC and memory management, as well as testing and quality assurance.

Jakarta EE 11: Beyond the Era of Java EE

This user guide provides a brief history of Java EE/Jakarta EE and a detailed overview of some of the specifications that will be updated in Jakarta EE 11.

Stable, Secure, and Affordable Java

Azul Platform Core is the #1 Oracle Java alternative, offering OpenJDK support for more versions (including Java 6 & 7) and more configurations for the greatest business value and lowest TCO.

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Step up your coding with the Continuous Feedback Udemy Course: Additional coupons are available

What do you know about the code changes that were just introduced into the codebase? When will you notice if something goes wrong?

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Dominika Tasarz

Administrator

I'm a community builder focused on growing the global Java and Jakarta EE ecosystems. I specialise in developer-focused marketing, community strategy and open source engagement, building strong and collaborative communities...

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Dominika Tasarz

Foojay Podcast #94: More Than...

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Foojay Podcast #94: More Than a Blog: How Foojay Connects, Sustains, and Evolves the Java Community

Table of Contents YouTubePodcast AppsContent Foojay.io, the website for the Friends of OpenJDK, is turning six years old. To celebrate, Frank Delporte headed to JCON in Cologne, Germany, and sat down with twelve members of the Java community to talk ...

May 04 228

Annelore Egger

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Buhake Sindi

Catherine Edelveis

Dominika Tasarz

François Martin

Frank Delporte

Geertjan Wielenga

Gerrit Grunwald

Iryna Dohndorf

Jago de Vreede

Markus Westergren

René Schwietzke

Conference

Java Java Beginner Java Core JavaPro Podcast

The Curious Case of Different Runtimes

Strange runtime behavior when presenting different training data to the JIT. We show how we diagnosed and condense down to a few test cases.

Jun 30 3,6K

René Schwietzke

Performance

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If you want to know what I spoke about in @jcon_conference in Germany, here's an interview I did at the @foojayio podcast:

#Java #JCON #JakartaEE #AI #A2A

02:06 PM · May 04, 2026

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Our team loves to meet and talk with the Java community from around the world. If you want to learn more. You can find all OmniFish presentations at: https://speakerdeck.com/omnifish, including links to the source code of related demos. Or get in touch for a free consultation call.

10:13 AM · April 30, 2026

Retweet on Twitter Foojay.io Retweeted

Another happy customer :)
"Their expertise and flexible hands-on troubleshooting support accelerated resolution of several unexpected hurdles and ultimately got us to a successful upgrade outcome."

If you would like to discuss how we could help your company, get in touch.

09:55 AM · April 21, 2026