Worked on the apache/logging-log4j2 repository, focusing on core stability and modernization over a two-month period. Addressed runtime errors on JREs lacking JMX support by removing the jvmrunargs lookup and cleaning related references, which improved reliability for downstream users. Enhanced test consistency by making timezone-related tests deterministic, ensuring reproducible builds. Upgraded the Elasticsearch Java Client to version 9.x, updating build configurations to support the latest features while maintaining compatibility. Utilized Java, build tools, and dependency management skills to reduce maintenance overhead and position the project for future enhancements, with all changes validated through targeted testing and code cleanup.