Worked on the hibernate/hibernate-orm repository to enhance stability in ORM lazy loading, particularly when using entity graphs. Addressed a ClassCastException in lazy associations by introducing a null-safe check for PersistentAttributeInterceptable and ensuring proper initialization of lazy fields. Developed a regression test suite to reproduce and validate the fix, focusing on a lazy one-to-one relationship scenario. This approach improved reliability for applications with complex ORM mappings by reducing runtime errors related to lazy loading. Utilized Java and Hibernate ORM internals, applying backend development skills and test-driven development practices to strengthen test coverage and maintain production stability.