21.10.0.0

Includes all October 2021 CVE fixes.

Azul Prime 21.10.0.0 contains the October 2021 CPU release of OpenJDK. Azul Prime 21.10.0.0 brings the associated JDK 7, JDK 8, JDK 11, JDK 13, and JDK 15 versions to October 2021 CPU security update levels.

The peak heap occupancy target, used by heuristics to decide when to trigger a garbage collection, is now managed dynamically by default. The dynamic changes can be disabled by setting GPGCTargetPeakHeapOccupancyPercent to a desired value.

Increased parallelism between collectors for the new generation and old generation. Helps reduce the peak duration for a new generation collection and reduce allocation delays during peak load.

The number of concurrent GC threads is now changed dynamically when -Xms is set to the same value as -Xmx, or when Azul Zing System Tools (ZST) is installed. At JVM start a low number of concurrent GC threads is employed. If later during application uptime the GC Time Percent metric increases beyond a threshold, more GC threads are added to reduce the number of GC cycles. The limit for the total number of GC threads is 3/4 of the process' available CPU threads. As of this Prime version, the number of threads will never shrink later.

To disable the dynamic handling, use the following on the command line: -XX:-UseDynamicNumberOfGCThreads

If one of the following flags is set on the command line, the dynamic handling will also be disabled:

General performance improvements.

More intrinsics from Java 17.