Worked on the spring-projects/spring-boot repository to deliver a targeted performance optimization for DevTools. Focused on backend development using Java, the work involved refactoring the ClassLoaderFiles component to use a pre-computed, flattened map for resource lookup. This technical approach reduced the complexity of resource-lookup operations from O(n*m) to O(m) or O(1), resulting in faster application restarts for large projects. The optimization preserved existing API compatibility, ensuring seamless integration for users. By improving performance without introducing breaking changes, the work enhanced developer experience and reduced build times, demonstrating a strong focus on performance optimization and maintainable Java development practices.