Worked on the apache/amoro repository to enhance the authentication user experience by refining backend error handling. Focused on improving login failure feedback, the developer replaced the ambiguous runtime exception message 'bad user' with the clearer 'invalid user,' providing users with more accurate guidance during authentication issues. This change, implemented in Java, aimed to reduce confusion and streamline support by making error prompts more descriptive. The work demonstrated attention to user-centric messaging and strong traceability, as each update was linked to a specific issue and commit. No major bugs were addressed during this period, with efforts concentrated on feature improvement.