Koichi Sakata
JVM Sustaining Engineer at Oracle Japan 日本オラクル
Chiyoda, Japan
Summary
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Rockstar🎓
Top SchoolKoichi Sakata is a JVM sustaining engineer and OpenJDK committer with 13 years of experience designing and tuning high-performance Java web applications across startups and enterprise teams. As founder of KanJava and a Java Champion, he blends community leadership and frequent conference speaking with hands-on expertise in GC algorithms, multithreading, and production debugging. He has led technical teams at NTT Data, Yahoo! JAPAN and others, architecting scalable APIs and cloud infrastructures (AWS, Spring Boot) while resolving hard runtime issues like OOM and concurrency bottlenecks. His open-source contributions to the flagship openjdk/jdk repository include fixes that improved build portability and tooling (IGV), reflecting deep familiarity with the JVM internals most teams never touch. Based in Chiyoda, Tokyo, he pairs a rare mix of operational JVM sustaining work and public-facing advocacy that helps bridge practitioner needs with the OpenJDK community.
13 years of coding experience
15 years of employment as a software developer
Department of Literature, Philosophy, Bachelor, Department of Literature, Philosophy, Bachelor at Kobe University
Japanese, English
Stackoverflow
101reputation
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Github Skills (10)
javas10
openjdk10
build-system10
jvm10
java10
cprogramming-language9
debug9
c-language9
debugging9
performance-optimization8
Programming languages (3)
Github contributions (5)
openjdk/jdk
Sep 2022 - Jan 2023
JDK main-line development https://openjdk.org/projects/jdk
Role in this project:
Back-end Developer
Back-end DeveloperContributions:12 reviews, 12 commits, 19 PRs in 4 months
Contributions summary:Koichi primarily contributed to the OpenJDK project by addressing build errors, fixing inconsistencies, and improving the codebase. They fixed build errors related to GCC 10 in several files, addressing potential issues with string operations and network interface configurations. They also worked on correcting issues in the Ideal Graph Visualizer (IGV), including fixes for incorrect display and tooltip issues.
openjdkjavajvmjdk
jyukutyo/jdk
Dec 2020 - Dec 2024
JDK main-line development
Contributions:40 pushes, 54 branches in 4 years
javajvmjdk
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