diff --git a/doc/release-notes/0.49/0.49.md b/doc/release-notes/0.49/0.49.md new file mode 100644 index 00000000000..99f0ea235c2 --- /dev/null +++ b/doc/release-notes/0.49/0.49.md @@ -0,0 +1,145 @@ + + +# Eclipse OpenJ9 version 0.49.0 release notes + +These release notes support the [Eclipse OpenJ9™ 0.49.0 release plan](https://projects.eclipse.org/projects/technology.openj9/releases/0.49.0/plan). + +## Supported environments + +OpenJ9 release 0.49.0 supports OpenJDK 8, 11, 17, 21, and 23. + +All releases are tested against the OpenJ9 functional verification (FV) test suite, the OpenJDK test suites, and additional tests provided by Adoptium. + +To learn more about support for OpenJ9 releases, including OpenJDK levels and platform support, see [Supported environments](https://eclipse.org/openj9/docs/openj9_support/index.html). + +## Notable changes in this release + +The following table covers notable changes in v0.49.0. Further information about these changes can be found in the [user documentation](https://www.eclipse.org/openj9/docs/version0.49/). + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Issue numberDescriptionVersion / PlatformImpact
N/AmacOS® 12 is out of supportAll versions (macOS 12)macOS 13 is the new minimum operating system level.
#20029The shared classes cache generation number is incremented.All versionsThe increment in the shared classes cache generation number causes the VM to create a new shared classes cache, rather than re-creating or reusing an existing cache. To save space, all existing shared caches should be removed unless they are in use by an earlier release. +The shared classes cache generation number is modified because of a change in the format of ROMClasses that are stored in the shared classes cache. A new flag J9AccClassIsShared is added to ROMClasses to indicate whether a ROMClass was loaded from a shared classes cache or from a VM. +
#20366A new shared classes cache suboption -Xshareclasses:extraStartupHints is added.All versionsBy default, you can add up to 64 startup hints only in a shared cache. You can use the -Xshareclasses:extraStartupHints=<number> option to adjust the number of startup hints that can be stored in a shared cache in addition to the default number.
#19872subAllocator related -Xgc options are added to control the compressed reference allocation.All versionsThe VM can use compressed references to decrease the size of Java objects and make better use of the available space in the Java heap. You can now control the compressed reference allocation with the following options: + + - -Xgc:suballocatorCommitSize=\ + - -Xgc:suballocatorIncrementSize=\ + - -Xgc:suballocatorInitialSize=\ + - -Xgc:suballocatorQuickAllocDisable + - -Xgc:suballocatorQuickAllocEnable
#20854Support for JDK Flight Recorder (JFR) in the VM is provided as a technical preview and a new option -XX:[+|-]FlightRecorder is added to enable or disable JFR.OpenJDK 11 and later (Linux® on x86 and Linux on AArch64)JFR is enabled by default and you can trigger the profile and diagnostic recording with the jcmd tool. You can disable JFR with the -XX:-FlightRecorder option.
+ +## Known issues + +The v0.49.0 release contains the following known issues and limitations: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Issue numberDescriptionVersion / PlatformImpactWorkaround
#15011The default stack size for the main thread is a smaller platform-dependent value.AllThe main thread stack size was 1 MB in releases before 0.32. In the 0.32 release and later it was modified to a smaller +platform-dependent value, the same value as the -Xmso setting. The 0.33 release increased the default -Xmso stack size +on x64 platforms, but builds with OpenJDK 17 and later also require more stack space to run. These changes might result in a +java.lang.StackOverflowError: operating system stack overflow.Use -Xmso to set the default stack size. See the default value by using -verbose:sizes.
#14803Using the -XX:+ShowHiddenFrames option in an OpenJ9 release that is built with OpenJDK 18 and later causes errors.All platformsWrong exception might be thrown when using the Reflection API.Avoid using the -XX:+ShowHiddenFrames option with OpenJDK 18 and later.
#13767Compressed references mode is not available.Apple silicon macOSYou can use only the large heap (non-compressed references) mode.None
+ +## Other changes + +A full commit history for 0.49.0 release is available at [Eclipse OpenJ9 v0.49.0](https://github.com/eclipse-openj9/openj9/releases/tag/openj9-0.49.0).