These release notes support the Eclipse OpenJ9™ 0.39.0 release plan.
OpenJ9 release 0.39.0 supports OpenJDK 20. For a list of JDK Enhancement Proposals (JEP) that are supported by or implemented in OpenJ9, see the release topic in the user documentation.
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.
The following table covers notable changes in v0.39.0. Further information about these changes can be found in the user documentation.
| Issue number | Description | Version / Platform | Impact |
|---|---|---|---|
| N/A | RHEL 8.4 is out of support. | All versions (RHEL 8.4) | RHEL 8.6 is the new minimum operating system level. |
The v0.39.0 release contains the following known issues and limitations:
| Issue number | Description | Platform | Impact | Workaround |
|---|---|---|---|---|
| #15011 | The default stack size is modified for the main thread. | All | The main thread stack size was 1 MB in releases prior to 0.32. In the 0.32 release and later it's modified to a smaller platform-dependent value, the same value as the -Xmso setting. The 0.33 release increases 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. |
| #13767 | Compressed references mode is not available. | Apple silicon macOS | You can use only the large heap (non-compressed references) mode. | None |
| #14803 | Using the -XX:+ShowHiddenFrames option in an OpenJ9 release that is built with OpenJDK 18 and later causes errors. | All platforms | Wrong exception might be thrown when using the Reflection API. | Avoid using the -XX:+ShowHiddenFrames option with OpenJDK 18 and later. |
| #6432 | If you mount the /proc file system with the hidepid=2 option on Linux® systems and the VM does not have root privileges, it cannot access the /proc/1/cgroup file and the container detection fails. | All versions (Linux) | The VM fails to start when the container detection code cannot access the /proc/1/cgroup file. | Remount the /proc file system with the hidepid=0 option or remount the /proc file system with the gid option to allow users in a certain group to access the /proc file system. |
A full commit history for 0.39.0 release is available at Eclipse OpenJ9 v0.39.0.