Stephan Schroevers
Computer Scientist at PicnicSupermarket
Netherlands, United Kingdom
Summary
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RockstarStephan Schroevers is a computer scientist with 12 years of experience building robust back-end systems and improving developer tooling, currently contributing at Picnic and previously at Fredhopper. He holds a BSc in Computer Science and an MSc in Logic from the University of Amsterdam, bringing both practical engineering and formal reasoning to his work. Stephan is an active open-source contributor to high-profile Java projects such as Mockito, Error Prone, Guava, and Immutables, where his patches improve testing, static analysis accuracy, and modern Java compatibility. His contributions show a focus on developer experience—adding better mock support for primitives and streams, reducing false positives in static checks, and modernizing APIs for newer JDKs. Colleagues value him for quietly refactoring messy internals into cleaner, more maintainable code and for catching subtle edge cases that improve long-term reliability. Based in the Netherlands and the UK, he pairs rigorous academic foundations with pragmatic engineering to ship dependable tooling used across the Java ecosystem.
11 years of coding experience
Stackoverflow
60,439reputation
9.3mreached
305answers
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Github Skills (81)
python10
builder-pattern10
annotations10
testing10
javas10
java-libraries10
refactoring10
static-analysis10
unix10
integer10
shell10
algorithm10
immutables10
test-driven-design10
guava10
Programming languages (13)
Github contributions (5)
google/error-prone
Aug 2017 - Jan 2023
Catch common Java mistakes as compile-time errors
Role in this project:
Back-end Developer
Back-end DeveloperContributions:115 reviews, 26 commits, 47 PRs in 5 years 5 months
Contributions summary:Stephan's contributions center on improving the `error-prone` tool, specifically addressing bugs and implementing new features related to code analysis and refactoring. They addressed issues like supporting the deletion of the last line of a file and preventing false positives in the `ConstructorLeaksThis` checker. Their work included modifications to core error-prone classes, test cases, and the inclusion of improvements like recognizing more `URLEqualsHashCode` violations. These changes likely enhanced the tool's accuracy and capabilities in identifying potential code issues.
compile-timemistakescompilestatic-code-analysisjava-common
mockito/mockito
Nov 2016 - Jan 2023
Most popular Mocking framework for unit tests written in Java
Role in this project:Back-end Developer & Test Automation Engineer
Back-end Developer & Test Automation EngineerContributions:2 reviews, 6 commits, 6 PRs in 6 years 2 months
Contributions summary:Stephan focused on enhancing the Mockito framework by introducing features related to handling primitive optionals, streams, and improving testing. They implemented default answers for these types, contributing to more comprehensive mocking capabilities. Further, they streamlined the testing code by factoring out redundant logic into helper methods. Additionally, the user added annotations and made improvements to support Error Prone integration.
test-automationjava-librarytestingmockitounit
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