Roy Van Rijn
Director OpenValue Rotterdam
Rotterdam and The Hague Netherlands
Summary
👤
Senior🎓
Top SchoolRoy Van Rijn is a technology leader and founder driving OpenValue Rotterdam as Director, blending hands-on software engineering with strategic architecture and agile leadership. With 14 years of experience, he has built a career spanning software development, architecture, and public speaking across international audiences, and he co-founded RotterdamJUG to nurture the Java community. A recognized Java Champion, JavaOne Rockstar, and Oracle ACE, he combines deep Java expertise with a track record of delivering scalable, high-performance systems. He actively contributes to open source and performance-focused projects, notably optimizing the One Billion Row Challenge in gunnarmorling/1brc through memory-mapped files, branchless parsing, and unsafe memory access techniques. In parallel, he leads GrepS as Managing Partner & Chief Assessment Officer, shaping software testing platforms and talent assessment. He holds a Bachelor of ICT and is based in Rotterdam and The Hague, Netherlands.
15 years of coding experience
15 years of employment as a software developer
Haagse Hogeschool/TH Rijswijk
English, German, Spanish
Stackoverflow
21reputation
824reached
1answer
0questions
Github Skills (13)
javas10
performance-optimization10
java10
bitwise10
algorithms8
data-structures8
algorithm8
data-structure8
ch8
inversion-of-control6
model-view-controller6
spring6
dependency-injection6
Programming languages (6)
Github contributions (5)
gunnarmorling/1brc
Jan 2024 - Feb 2024
Role in this project:
Back-end Developer / Performance Engineer
Back-end Developer / Performance EngineerContributions:28 reviews, 32 PRs, 50 comments in 1 month
Contributions summary:Roy's contributions primarily focus on optimizing the performance of a Java program for the One Billion Row Challenge. Their initial implementation involved parallel processing and BufferedReader. Subsequent commits demonstrate significant performance improvements through techniques like memory-mapped files, branchless parsing, and bitwise operations (SWAR). Further enhancements include the use of unsafe memory access, and the user demonstrates strong ability in performance optimization.
royvanrijn/Quantastic
Jun 2018 - May 2024
Contributions:6 pushes, 1 branch in 5 years 11 months
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