Eclipse OpenJ9 version 0.30.0 release notes
These release notes support the Eclipse OpenJ9 0.30.0 release plan.
Supported environments
OpenJ9 release 0.30.0 supports OpenJDK 8, 11 and 17.
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.
Notable changes in this release
The following table covers notable changes in v0.30.0. Further information about these changes can be found in the user documentation.
| Issue number |
Description |
Version / Platform |
Impact |
| #13199 |
Changes to the shared classes cache generation number |
All versions |
The format of classes that are stored in the shared classes cache is changed, which causes the JVM to create a new shared classes cache rather than re-creating or reusing an existing cache. To save space, you can remove all existing shared caches unless they are in use by an earlier release. |
| #13579 |
Java dumps now identify any command-line arguments that were ignored. |
All versions |
If any arguments are ignored, the group is introduced with 1CIIGNOREDARGS, followed by a line beginning with 2CIIGNOREDARG for each ignored argument. |
| #14042 |
New -XX:[+|-]EnsureHashed option added |
All versions |
This option specifies/unspecifies classes of objects that will be hashed and extended with a hash slot upon object creation or first move. This option may improve performance for applications that frequently hash objects of a certain type. |
| #12043 |
Redesigned balanced GC policy heap resizing |
All versions |
Eden and non-Eden heap resizing heuristics are redesigned to include more criteria (CPU overhead, heap occupancy, pause target time) and their relative sizing for fully expanded heap is made far more dynamic. A few existing command line options for fine tuning of resizing heuristics are now made avaialable for balanced GC policy, too. |
Known issues
The v0.30.0 release contains the following known issues and limitations:
| Issue number |
Description |
Platform |
Impact |
Workaround |
| #14192 |
Creating a system (core) dump on macOS 12 or later results in an error pwrite() error writing segment data:: Bad address and no system dump created. |
macOS |
Certain types of problems cannot be diagnosed. System dumps cannot be created by the user for analysis. |
Use a macOS version lower than 12. |
Other changes
A full commit history for this release is available at Eclipse OpenJ9 v0.30.0.
