Worked on improving the reliability and correctness of the Drools rule engine within the apache/incubator-kie-drools repository. Focused on fixing activation group handling to ensure that activation groups are properly applied after a rule fires, addressing issues with rule reactivation within the same group. Introduced a dedicated unit test to validate activation group reactivation, reducing the risk of regressions and enhancing rule execution reliability. Utilized Java for rule engine development and leveraged the TrackingAgendaEventListener to monitor activation group transitions, which improved observability and debuggability. These changes contributed to more stable production rule sets and reduced maintenance overhead in enterprise environments.