Worked on the apache/paimon repository over a two-month period, focusing on backend quality and user experience rather than feature delivery. Addressed three impactful bugs using Java and disciplined unit testing, including a robustness improvement in the snapshot commit workflow by adding existence checks after failed rename operations to reduce operational risk. Enhanced documentation clarity by correcting HTML rendering issues and improved error messaging in TagManager to minimize user confusion. Emphasized defensive programming and precise technical writing, ensuring that both code and documentation changes directly reduced user-facing failures and support friction while maintaining stability in core backend modules and workflows.