Jon Nilsen
Software Development Engineer at Amazon Web Services (AWS)
Seattle, Washington, United States
Summary
🤩
Rockstar🎓
Top SchoolJon Nilsen is a Software Development Engineer at AWS in Seattle with six years of professional experience and a BS in Computer Science from Central Washington University. He is a practical systems engineer focused on low-latency, high-stability runtime work, contributing significant fixes and enhancements to the Shenandoah garbage collector in OpenJDK. His contributions span core GC components, aarch64-specific refactors, heuristics tuning, and lock contention fixes that improve performance and robustness in a widely used JVM. Active in real-time Java design since the mid-1990s, he brings deep familiarity with runtime constraints and concurrency trade-offs uncommon for his experience level. Colleagues rely on him for thoughtful, durable fixes rather than quick patches, and he balances production-impact engineering with ongoing open-source stewardship.
6 years of coding experience
Bachelor of Science - BS, Computer Science, Bachelor of Science - BS, Computer Science at Central Washington University
Github Skills (13)
openjdk10
javas10
c-language10
jvm10
cprogramming-language10
performance-optimization10
java10
concurrency10
garbage-collection10
system-design9
software-design9
sys9
arm9
Programming languages (3)
Github contributions (5)
openjdk/jdk
Nov 2020 - Jul 2026
JDK main-line development https://openjdk.org/projects/jdk
Role in this project:
Back-end Developer
Back-end DeveloperContributions:491 reviews, 33 PRs, 520 comments in 5 years 8 months
Contributions summary:Jon primarily contributes to the Shenandoah garbage collector within the OpenJDK project, focusing on improvements and bug fixes. Their work involves modifying core GC components, including the free set, control thread, and heuristics. The user also implements and refactors aspects of the Shenandoah collector on the aarch64 architecture, as well as fixing lock contention issues. These changes enhance the performance and stability of the garbage collector.
openjdkjavajvmjdk
openjdk/shenandoah
Jan 2021 - Jan 2023
https://openjdk.org/projects/shenandoah
Contributions:663 reviews, 37 commits, 90 PRs in 2 years
openjdkjavajsinterop
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