Theresa Cayer
Software Engineer at IBM
Old Toronto, Ontario, Canada
Summary
🤩
Rockstar🎓
Top SchoolTheresa Cayer is a software engineer with 11 years of experience building and optimizing language runtimes, currently contributing to the Eclipse OpenJ9 JVM at IBM. She brings deep C/C++ and Java expertise from work on OpenJ9 and Eclipse OMR, with notable contributions to bytecode verification, interpreter optimizations, and cross-platform runtime stability and security. Theresa pairs hands-on systems engineering with developer advocacy—she’s delivered talks at major Java conferences and translated community needs into product features while mentoring new engineers. Her background spans research and prototype work on native-image and Snapshot+Restore technologies at Red Hat as well as developer-focused security tooling at Sonatype. Outside of code she volunteers with animal rescues and experiments with refining a homemade ice cream recipe, reflecting a practical curiosity that also shows up in low-level performance tweaks.
11 years of coding experience
7 years of employment as a software developer
Bachelor of Applied Science (B.A.Sc.), Computer Engineering, Bachelor of Applied Science (B.A.Sc.), Computer Engineering at The University of British Columbia
English, French
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (19)
c-language10
jvm10
multiplatform10
verification10
java-bytecode10
cross-platform10
java10
javas10
performance-optimization10
bytecode10
omr10
cprogramming-language10
testing9
character-encoding9
signal-handling9
Programming languages (11)
Github contributions (5)
eclipse-openj9/openj9
Sep 2017 - Jan 2021
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 & Performance Engineer
Back-end Developer & Performance EngineerContributions:383 reviews, 171 commits, 336 PRs in 3 years 4 months
Contributions summary:Theresa's contributions primarily focused on improving the OpenJ9 JVM, specifically related to Java bytecode verification and record class support. They implemented error handling for compiler and class file reader related issues, and added instrumentation tests for JSR292 and JSR335. Additionally, the user refactored code related to the bytecode interpreter to reduce memory copies and optimize performance, and added support for new JVM features.
eclipsejavaomropenj9openjdk
eclipse-omr/omr
Mar 2018 - Nov 2020
Eclipse OMR™ Cross platform components for building reliable, high performance language runtimes
Role in this project:Back-end Developer
Back-end DeveloperContributions:3 reviews, 11 commits, 9 PRs in 2 years 8 months
Contributions summary:Theresa contributed to the Eclipse OMR project, focusing on low-level system and platform-specific code. Their work involved enabling Windows stack protection flags, fixing compile errors, and converting character encodings (mutf8 to latin1) within the porting layer. Additionally, they made changes to GC thread management and signal handling code. The user’s contributions directly impact the runtime environment's stability, security, and cross-platform compatibility.
eclipseomrruntimes
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