During their tenure, Fmeum focused on enhancing the reliability of system metrics in the corretto/corretto-21 repository. They addressed a critical bug in the Java OperatingSystemMXBean by introducing null-safe handling to the system CPU load calculation on Unix platforms. Using Core Java and system programming expertise, Fmeum modified the isCpuSetSameAsHostCpuSet logic to defensively guard against null values in container metrics and CPU set data. This targeted fix prevented potential NullPointerExceptions, reducing the risk of runtime failures and misleading monitoring data. Their work improved the stability of production metrics reporting, demonstrating careful attention to robust, defensive coding practices.