Worked on the apache/ignite repository to enhance API clarity by updating the IndexQuery.getCriteria method. Focused on API design and code documentation using Java, the developer annotated getCriteria with @Nullable to accurately reflect its potential to return null. This adjustment clarified the API contract, reducing the risk of downstream null-pointer exceptions for users of IndexQuery. The change aligned with broader API reliability efforts and was implemented with minimal impact on existing code. By improving documentation and explicitly signaling nullability, the work contributed to safer and more predictable API usage, supporting maintainability and reliability for future development within the project.