Graham Chapman
Senior Software Developer at IBM Canada Ltd.
Ottawa, Ontario, Canada
Summary
🤩
Rockstar🎓
Top SchoolGraham Chapman is a Senior Software Developer based in Ottawa with nine years of modern experience and a long career focused on low-level systems and JVM internals. At IBM he works on the Java Virtual Machine, contributing to stability and performance in areas like JNI interoperability and class redefinition. His open-source work on Eclipse OMR and OpenJ9 shows deep expertise in atomic operations, memory barriers, and architecture-specific optimizations for x86 and s390. He combines C/C++ runtime debugging with practical fixes that improve cross-platform memory semantics, demonstrating an engineer comfortable at the hardware-software boundary. Collected across commercial and open-source projects, his contributions emphasize robustness and performance rather than feature surface area. He holds a Computer Science degree from Carleton and brings a pragmatic, systems-first mindset to complex runtime problems.
9 years of coding experience
6 years of employment as a software developer
Bachelor, Computer Science, Bachelor, Computer Science at Carleton University
Github Skills (24)
debugging10
debug10
c-language10
jvm10
multithreading10
atomics10
memory-management10
jna10
atomic10
cprogramming-language10
assembly9
x869
performance-optimization9
optmization9
optimisation9
Programming languages (3)
Github contributions (5)
eclipse-openj9/openj9
Oct 2017 - Jan 2023
Eclipse OpenJ9: A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput. Builds on Eclipse OMR (https://github.com/eclipse/omr) and combines with the Extensions for OpenJDK for OpenJ9 repo.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1153 reviews, 875 commits, 997 PRs in 5 years 4 months
Contributions summary:Graham primarily focused on debugging and fixing issues related to native method prefixing and class redefinition within the Eclipse OpenJ9 JVM. They addressed problems in Fast JNI by correcting the prefix removal logic and ensuring the correct methods were called. The contributions included code modifications in the C++ runtime environment to resolve compilation and runtime issues. Their work appears to improve the stability and robustness of Java's JNI interoperability.
runtimecompilerextensionseclipseomr
eclipse-omr/omr
Jul 2016 - Jul 2020
Eclipse OMR™ Cross platform components for building reliable, high performance language runtimes
Role in this project:Back-end Developer
Back-end DeveloperContributions:11 reviews, 41 commits, 39 PRs in 4 years 1 month
Contributions summary:Graham primarily contributed to the Eclipse OMR project by enhancing atomic operations and memory management. They implemented an optimization for atomic compare and swap operations, specifically targeting x86 and s390 processors, and added the bitOrU32 function. Furthermore, the user made improvements to memory barrier mechanisms on Windows MSVC and fixed memory fence implementations on x86. These changes demonstrate a focus on low-level system programming and optimization for different processor architectures.
jitruntimesomrruntimeportability
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.