Worked on apache/hadoop and apache/hbase repositories, focusing on reliability and data integrity in distributed systems. Addressed a critical issue in HDFS by fixing observer namenode block location retrieval under network delays, adding validation and dedicated test coverage to ensure accurate metadata responses. In apache/hbase, implemented snapshot expiration checks within backup and restore workflows, introducing robust exception handling and validation logic to prevent the use of invalid snapshots. Leveraged Java, HDFS, and HBase expertise to enhance system robustness, collaborating across teams to validate solutions. The work emphasized careful validation, exception management, and test-driven development to reduce data inconsistencies and outages.