Worked on the tf-nira/registration-client repository to enhance backend validation logic using Java. Focused on improving data integrity by consolidating age and years-lived validation, ensuring that an applicant’s years lived at a residence cannot exceed their age. Addressed a previous strict comparison by implementing a controlled rollback, stabilizing the validation flow and maintaining consistency. Integrated age persistence within the GenericController to support cross-validation scenarios, and refactored validation logic for maintainability. The work combined backend development and Java expertise, emphasizing robust validation mechanisms and careful management of controller state to support accurate and reliable data processing within the application.