During May 2025, Hsu Hweek refactored temporary directory handling in the payara/Payara and vespa-engine/vespa repositories, focusing on standardizing and modernizing temp-dir creation. By replacing custom logic with Java NIO’s Files.createTempDirectory, Hsu improved reliability, error handling, and maintainability across both codebases. The work involved updating API signatures and call sites, ensuring safer parallel operations and reducing boilerplate. Using Core Java, Java NIO, and robust refactoring practices, Hsu’s changes streamlined file I/O processes and mitigated temp-dir related failures. This targeted engineering effort enabled cleaner APIs and accelerated future enhancements, demonstrating thoughtful depth in cross-repository code modernization and risk management.