Java OpenJDK April 2026 Patch & Security Update

Microsoft has released the April 2026 patch and security update for the Microsoft Build of OpenJDK, covering versions 11, 17, 21, and 25. Key highlights for OpenJDK 25 include a Windows AArch64 Safefetch bug fix, implementation of time-based G1 heap uncommit during idle periods (useful for containerized and cloud workloads), and AOTCache updates including an MXBean for programmatic control of training data recording. OpenJDK 21 and 17 also receive the Windows AArch64 Safefetch fix. Source code for all builds is available on GitHub, and links to upstream vulnerability advisories and Oracle's consolidated release notes are provided.