Worked on the mybatis/mybatis-3 repository to deliver an API enhancement focused on the mapper binding layer. Developed and introduced the MapperMethodInvoker as a public interface, moving it from a nested scope to its own file to improve modularity and accessibility. This refactor, implemented in Java, addressed issue #3414 by strengthening the API surface for the mapper proxy mechanism, making it more extensible and easier to test. The work demonstrated skills in API design and software architecture, enabling downstream modules to integrate more effectively with the mapper proxy and supporting future enhancements to the codebase’s structure and maintainability.