Johan Sjölén
Senior Member Of Technical Staff at Oracle
Malmo, Sweden
Summary
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Rockstar🎓
Top SchoolJohan Sjölén is a systems-focused Senior Member of Technical Staff with four years of professional experience building and optimizing the OpenJDK JVM runtime at Oracle. He brings deep low-level expertise in virtual machines, lock-free concurrency, memory models across CPU architectures, bytecode interpretation, and STL-less C++14, complemented by practical experience in Go, C, Linux and cloud during earlier roles. Johan has shipped performance-sensitive components like asynchronous logging circular buffers, alternative memory allocators for the C2 compiler, and a native memory tracker based on treaps — work that lives in open source on the OpenJDK GitHub. Based in Malmö, Sweden, he pairs an MSc in Computer Science from KTH with a pragmatic engineering style that favors measurable throughput and memory improvements. Not obviously stated: he operates comfortably across assembly for multiple ISAs and advanced virtual memory techniques, making him especially effective on platform and runtime problems. He is approachable and active in open-source review workflows, inviting collaboration via his public PRs.
4 years of coding experience
7 years of employment as a software developer
Master of Science in Engineering (MSc), civilingenjör, Computer Science, Master of Science in Engineering (MSc), civilingenjör, Computer Science at KTH Royal Institute of TechnologyLasse-Maja dagis
Stackoverflow
133reputation
5kreached
3answers
2questions
Github Skills (21)
jvm10
jgss10
java10
openjdk10
gssapi10
adoptopenjdk10
eclipse8
html6
hyperledger-composer6
hyperledger-fabric6
concurrency6
openj96
css6
jquery6
security6
Programming languages (2)
Github contributions (5)
johan-sjolen/jdk
Apr 2022 - Jun 2026
JDK main-line development
Contributions:2003 pushes, 268 branches, 2 comments in 4 years 3 months
javajvmjdk
jdksjolen/jdksjolen.github.io
May 2023 - Feb 2025
Contributions:1 push, 1 branch in 1 year 8 months
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