Worked on the Java build systems within the facebook/buck2 and facebook/buck2-prelude repositories, focusing on simplifying classpath handling to improve maintainability and reduce risk. Addressed two bugs by reverting previous changes that had introduced unnecessary complexity in classpath_targets for Java rules. Used Starlark and Java build tools to consolidate classpath information, ensuring that get_classpath_subtarget now returns only the classpath, streamlining the build process. Applied a consistent approach across both repositories, which reduced the surface area of the build logic and strengthened long-term reliability for Java rule execution. The work emphasized clarity and maintainability in build system engineering.