Worked on the apache/rocketmq repository over a two-month period, focusing on backend reliability and high-availability stability. Addressed critical bugs in Java, improving error handling and robustness in controller address management and enhancing logging for better observability in multi-controller deployments. Applied static analysis and Checkstyle compliance to maintain code quality. Further contributions included targeted fixes to high-availability paths, such as resolving synchronization issues in HAService and ensuring safe data truncation to prevent inconsistencies. Improved compatibility with newer JDKs and strengthened unit testing coverage. Utilized Java, Maven, and API integration skills to deliver more reliable and maintainable backend infrastructure.