GerardĀ Klijs
Software Engineer at Alliander
Nijmegen, Gelderland, Netherlands
Summary
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Rockstarš
Top SchoolGerard Klijs is a pragmatic software engineer with nearly 15 years in development and nine years of focused industry experience building scalable Java backends and event-driven systems. He has worked across open-source and commercial settingsāfrom AxonIQ where he contributed stability and concurrency fixes to the Axon Framework, to his current role at Allianderābringing deep expertise in Spring Boot, event streaming, and event sourcing. Gerard regularly speaks at conferences like GraphQL Summit and Kafka Summit and contributes to OSS projects, combining practical production hardening with community-driven design. He explores languages such as Rust, Clojure and Kotlin outside core hours, reflecting a curiosity for alternative paradigms that inform his JVM work. Based in Nijmegen, he balances technical rigor with approachable knowledge sharing and a tendency to think about software that can evolve gracefully over time. An eclectic reader and bass player, he brings the same patient, iterative mindset to architecture and debugging as he does to learning new instruments.
9 years of coding experience
13 years of employment as a software developer
Bachelor of Science, Master of Science, Cognitive Artificial Intelligence, Bachelor of Science, Master of Science, Cognitive Artificial Intelligence at Utrecht University
Dutch, English
Stackoverflow
391reputation
5kreached
29answers
0questions
Github Skills (16)
javas10
event-handling10
multithreading10
java10
concurrency10
axon-framework10
domain-driven-design9
event-sourcing9
cqrs9
spring-cloud6
exceptions6
axon6
apache-kafka6
architecture6
spring-boot6
Programming languages (13)
Github contributions (5)
AxonFramework/AxonFramework
Jun 2022 - Jan 2023
Framework for Evolutionary Message-Driven Microservices on the JVM
Role in this project:
Back-end Developer
Back-end DeveloperContributions:367 reviews, 73 commits, 92 PRs in 7 months
Contributions summary:Gerard implemented retry mechanisms for token store initialization within the PooledStreamingEventProcessor, addressing potential concurrency issues. They migrated token store initialization to the coordinator within the same processor, enhancing its stability and startup behavior. Furthermore, the user fixed an issue where the number of available threads could become lower than the initial value during shutdown of the Tracking Event Processor. The user also improved the concurrent behavior of the tracking event processor.
event-sourcingaxon-frameworkaxoncqrsperformance
gklijs/bank-axon-graphql
Nov 2020 - Aug 2022
Version of the open bank, using Axon instead of Kafka.
Contributions:31 commits, 2 PRs, 34 pushes in 1 year 9 months
bankkafkagraphql-subscriptionsaxon
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