Lars Westergren
Software Engineer at Swedish Police Authority
Greater Stockholm Metropolitan Area Sweden
Summary
👤
Senior🎓
Top SchoolLars Westergren is a seasoned software engineer based in Greater Stockholm with 13 years of professional experience building backend systems across Java, Ruby, Scala and Rust. He has a strong track record as a senior consultant and tech lead delivering robust, high-uptime systems for industries ranging from telecom eSIM provisioning and energy interoperability to EV charging and healthcare logistics. Lars contributes to open source at scale — notable work on the JRuby project involved improving the OpenSSL extension and PKCS12 handling — reflecting a pragmatic focus on security and correctness. Comfortable across legacy modernization and cloud-native stacks, he teaches and evangelizes functional programming and Java 8 lambdas, and often pairs hands-on coding with mentoring and architectural guidance. Colleagues know him as a methodical problem solver who seeks fulfilling work that improves the world while continuously learning from skilled peers.
13 years of coding experience
9 years of employment as a software developer
Asian Studies, Asian Studies at University of AdelaideComputer Science, Computer Science at UdacityMaster Computer Science, Master Computer Science at Uppsala University
English, Swedish, German
Stackoverflow
2,129reputation
501kreached
36answers
10questions
design-patterns
top-5%
Github Skills (14)
javas10
bouncy-castle10
pkcs10
openssl10
java10
ruby10
jvm9
design-patterns9
release-management6
oop6
exceptions6
language-agnostic6
akka6
scala6
Programming languages (2)
Github contributions (5)
jruby/jruby
Jan 2013 - Oct 2013
JRuby, an implementation of Ruby on the JVM
Role in this project:
Back-end Developer
Back-end DeveloperContributions:6 commits in 9 months
Contributions summary:Lars contributed to the JRuby project, focusing on the OpenSSL extension. Their work involved updating dependencies, specifically upgrading BouncyCastle jars. They also addressed and tested issues related to PKCS12 format, including file reading and UTF8 string handling. Further contributions included code cleanup and bug fixes related to PKCS12 initialization.
ruby-languageconcurrencyrubyjvmperformance
LarsWestergren/scala
Aug 2022 - Sep 2022
Exercism exercises in Scala.
Contributions:21 pushes, 5 branches in 18 days
scalaexercismexercism-exercises
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