Jonas Berg
Software Developer at RELEX
Helsinki, Finland
Summary
👤
Senior🎓
Top SchoolJonas Berg is a pragmatic software developer with 12 years of experience, based in Helsinki, who blends deep Java and JRuby backend expertise with practical work on internal tooling, dependency management and CI automation. At RELEX he moved from customising supply-chain software to improving an in-memory columnar database and optimizing performance as part of his M.Sc. thesis, and today contributes upstream to open-source tools while maintaining licensing and vulnerability workflows. He has hands-on experience fixing numerical precision in JRuby’s BigDecimal implementation and improving its test coverage, demonstrating attention to correctness in complex runtime code. Comfortable mentoring students (Scala, low-level programming) and running ops at scale, he pairs analytical rigor with wide-ranging curiosity—languages, etymology and puzzles—that helps him approach problems from multiple perspectives.
12 years of coding experience
Master of Science (M.Sc.), Computer Science, Pass with Honours, Master of Science (M.Sc.), Computer Science, Pass with Honours at Aalto UniversityMatriculation Examination, Matriculation Examination at Närpes Gymnasium
English, Swedish, Finnish, French, Japanese, German
Github Skills (7)
bigdecimal10
ruby10
testing9
jvm7
concurrency7
performance-monitor6
performance-analysis6
Programming languages (7)
Github contributions (5)
jruby/jruby
Oct 2017 - Nov 2017
JRuby, an implementation of Ruby on the JVM
Role in this project:
Back-end Developer
Back-end DeveloperContributions:5 commits, 3 PRs, 5 comments in 8 days
Contributions summary:Jonas primarily contributed to the `RubyBigDecimal` class, implementing and fixing functionality related to precision and scaling. Their work focused on ensuring the BigDecimal's limit feature worked correctly for subtraction and division operations. They also updated the testing suite to validate these BigDecimal operations. Additionally, the user refactored code, replacing the use of direct class comparisons with `instanceof` checks.
ruby-languageconcurrencyrubyjvmperformance
MrBerg/DependencyCheck
Mar 2016 - Aug 2018
OWASP dependency-check is a utility that detects publicly disclosed vulnerabilities in application dependencies.
Contributions:1 push, 4 branches in 2 years 5 months
sarifdependenciessecurity-toolsbugbountysecurity
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