Worked on modernizing the denoland/chromium_build repository by updating its build system to support JDK 21, focusing on compatibility with Kythe integration. Addressed a key issue by removing the conditional enforcement of JDK 17 for Kythe annotations, allowing the build to run seamlessly with the Kythe Java extractor under JDK 21. This change streamlined the Java development environment and reduced upgrade risks for downstream pipelines. The work involved build system configuration using GN and Python, emphasizing careful management of Java toolchains. The update improved maintainability and ensured that the build process remains aligned with evolving Java tooling standards.