Boris Spasojević
Principal Researcher at Oracle
Zurich, Zurich, Switzerland
Summary
👤
Senior🎓
Top SchoolBoris Spasojević is a Principal Researcher at Oracle in Zurich with over a decade of experience engineering high-performance language runtimes and JIT compilers, primarily within the GraalVM and Truffle ecosystems. He combines deep research-led expertise (PhD-level) with hands-on backend development, contributing to flagship open-source projects like GraalJS, GraalPy and GraalVM core components focused on optimization, profiling and bytecode generation. His work frequently targets polymorphism handling, node-level performance tuning and tooling around Truffle instrumentation—areas that require both systems-level rigor and subtle heuristic design. Previously he built compilers and platform tooling in embedded and toolchain contexts, bringing practical low-level optimization experience from industry and academia. He also mentors students and has a track record of improving developer tooling and language-agnostic profilers, reflecting a blend of mentorship and production impact. Based in Zurich, he speaks the language of both research and shipping resilient, high-throughput runtime systems.
12 years of coding experience
9 years of employment as a software developer
Doctor of Philosophy (PhD), Computer Science, Doctor of Philosophy (PhD), Computer Science at University of BernMSc, Computing and Automatics, major field: Computer techniques and computer communication., 10/10, MSc, Computing and Automatics, major field: Computer techniques and computer communication., 10/10 at Univerzitet u Novom Sadu
Serbian, English, German
Github Skills (17)
javascript10
graalvm10
back-end-development10
python10
testing10
instrumentation10
java10
ruby10
javas10
truffleruby10
performance-optimization10
truffle10
cpu-profiling10
embeddable9
cicd8
Programming languages (7)
Github contributions (5)
graalvm/simplelanguage
Feb 2018 - Oct 2022
A simple example language built using the Truffle API.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:240 commits, 89 PRs, 40 pushes in 4 years 8 months
Contributions summary:Boris primarily contributed to the development of a simple language using the Truffle API, focusing on implementing core language features. Their work involved adding a launcher sub-project, updating the language implementation, and updating and modifying the Java files. The user also made changes to testing files and added a script for automating repository updates. The user's contributions are aimed at enhancing and refining the SL language project's functionality and structure.
ethereumapitruffleblockchain
oracle/graal
May 2017 - Mar 2026
GraalVM compiles applications into native executables that start instantly, scale fast, and use fewer compute resources 🚀
Role in this project:Back-end Developer
Back-end DeveloperContributions:12 reviews, 25 PRs, 169 comments in 8 years 11 months
Contributions summary:Boris's contributions are focused on the GraalVM project, particularly within the tools and runtime components related to CPU profiling. They made changes to the CPUSampler, including initial cleanup, implementation of the takeSample function, and refactoring code related to the handling of classes and the inclusion of runtime information such as frame information and profile data. The user also made adjustments to SourceSectionFilter, dealing with root nodes and addressing licence issues.
graalvmjavaaotcompiler
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