Worked on backend reliability and maintainability for apache/polaris and its Renovate fork, focusing on concurrency, event-driven architecture, and code quality. Enhanced in-memory event processing by introducing a dedicated EventProcessor with explicit locking, replacing less robust synchronization and improving shutdown safety. Centralized credential rotation logic into a shared utility, reducing duplication and ensuring consistent policy enforcement across authorizers. Improved documentation clarity and fixed test output formatting to aid maintainability. Used Java and Python for backend development, buffer management, and unit testing, delivering features and bug fixes that strengthened thread safety, reduced ambiguity, and improved the reliability of concurrent event handling workflows.