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Zing Virtual Machine Release Notes

Release date: May 29, 2020

Version 1.1

This document provides release information for Zing Virtual Machine

What's New

Below is the list of new features and updates introduced in Zing Virtual Machine

Java Flight Recorder Tick Profiler Enhancement

In ZVM, the Java Flight Recorder Tick Profiler becomes enabled by default.

See Using Zing JFR Tick Profiler for more information.

Java Monitors Relocation

In ZVM, Java monitors are moved from CodeCache to a new dedicated MonitorCache storage.

See Monitor Cache Use Optimization Options for related command-line options.

Performance Improvements

  • The release of ZVM includes optimizations targeted at accelerating compilation and warmup.

  • ZVM introduces better JDK 11 java.lang.StackWalker which is frequently used by log4j2 and other logging implementations.

    See also and java.lang.StackStreamFactory$AbstractStackWalker.

  • ZVM provides a reduction of application exit times in the non-ZST mode when a process uses mlockall().

Improved JCC Erratum SKX102 Mitigation Strategy

ZVM improves the mitigation strategy used by the Falcon compiler to minimize performance impacts due to Intel's microcode updates in response to Jump Conditional Code (JCC) Erratum SKX102. Previous versions inserted nop instructions for padding; the new version can optionally increase the size of existing instructions in some cases. As before, the mitigation is enabled only on affected processors, and no user action is needed.

Zing Testing Grace Period Mode

ZVM introduces a testing grace period mode, under which the Zing JVM can run for up to 60 minutes (3600 seconds) without requiring a valid license. The testing grace period can be enabled by setting the ZING_TESTING_GRACE_PERIOD_SEC environment variable to a number of grace period seconds (up to 3600), or by using the -XX:ZingTestingGracePeriodSec=N flag with a similar value.

See Zing Testing Grace Period Mode for details.

Resolved Issues

The following table contains issues resolved in the release of Zing Virtual Machine

Bug ID Description

Crash in guarantee(FMP.getNumFunctions() == 1) failed: exactly one function expected!


Crash with problematic frame vframe::next()+0x9e


Crash in guarantee(false) failed: derived_oop_slots.contains(dst)!!

Common Vulnerabilities and Exposures Fixes

The list of latest Common Vulnerabilities and Exposures (CVE) fixes included in ZVM is available in Common Vulnerabilities and Exposures Fixes.

Check out links below for more in-depth information on release history for Zing:



Last modified: June 1, 2020

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