René Gielen
Aachen, North Rhine-Westphalia, Germany
Summary
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RockstarRené Gielen is a seasoned software craftsman and coach based in Aachen, Germany, with 20 years of experience building and hardening backend systems. He is an active open source contributor and Open Source Fellow who has worked on high-profile projects like Apache Struts, contributing both framework-level security improvements and pragmatic DevOps fixes. René blends deep Java/MVC expertise with practical infrastructure skills—adding JNDI lookup support, tightening parameter handling, and streamlining Docker-based site builds. As a trainer and mentor he focuses on sustainable craftsmanship and team enablement, helping teams adopt robust, maintainable practices. An avid diver off work, he brings the same calm, meticulous approach underwater to diagnosing tricky production issues. Not obvious at first glance: he frequently tackles behind-the-scenes build and deployment problems that keep projects reliably runnable in diverse environments.
20 years of coding experience
Stackoverflow
176reputation
6kreached
8answers
0questions
Github Skills (18)
docker10
struts10
dockers10
java10
security10
javas10
jekyll10
web-framework10
jndi9
bash8
tomcat6
key-event6
controlsfx6
event-handling6
jdbc6
Programming languages (6)
Github contributions (5)
apache/struts
Feb 2012 - Jan 2016
Apache Struts is a free, open-source, MVC framework for creating elegant, modern Java web applications
Role in this project:
Back-end Developer
Back-end DeveloperContributions:2 reviews, 71 commits, 1 PR in 3 years 11 months
Contributions summary:René primarily focused on improving the Apache Struts framework. Their commits involved adding support for servlet container JNDI lookup and custom configuration constants to override standard lookups. They addressed a thread local cleanup issue and decoupled token names from session attribute names. Additionally, they implemented parameter name length restrictions to enhance the security of the framework.
javamvc-frameworkstrutsweb-framework
apache/struts-site
Nov 2012 - Nov 2020
Mirror of Apache Struts site
Role in this project:DevOps Engineer
DevOps EngineerContributions:41 commits, 3 PRs, 18 pushes in 8 years 1 month
Contributions summary:René's contributions primarily focused on infrastructure and deployment aspects of the Apache Struts site. They adjusted Docker scripts and documentation to resolve start errors and enable local serving, ensuring the site's build and execution. The user also updated the site's content, adding a security announcement, which suggests involvement in site maintenance, but their primary focus was on improving the site's infrastructure and build processes. This included managing docker configurations.
strutsweb-frameworkjava
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