What's new in version 0.18.0
The following new features and notable changes since v 0.17.0 are included in this release:
- jextract now available on macOS for OpenJDK version 8
- New shared classes cache suboption to turn off timestamp checking
-Xmso1 MB minimum value on z/OS 64-bit
- New Java™ statistics monitoring (
- -XX:+TransparentHugePage is enabled by default on more Linux systems
- Add new Xdump exit agent and ExitOnOutOfMemoryError option
- LUDCL caching enabled by default
- Terabytes suffix support for -X and -XX options that take a size
- Improved support for pause-less garbage collection
- Add more changes here...
Features and changes
jextract now available on macOS for OpenJDK version 8
jextract tool is now available on macOS® platforms (as well as AIX® and Linux®) for all current versions of OpenJDK: 8, 11, and 13.
New shared classes cache suboption to turn off timestamp checking
You can set the
-Xshareclasses:noTimestampChecks option to turn off timestamp checking in shared classes. For more information, see the -Xshareclasses:noTimestampChecks option.
-Xmso 1 MB minimum value on z/OS 64-bit
On z/OS 64-bit,
-Xmso has a 1 MB minimum value, to match the minimum stack space provided by the operating system. If you set a value smaller than 1 MB, the value is ignored.
New jstat tool
For compatibility with the HotSpot implementation, OpenJ9 now includes an independent implementation of the
jstat tool for retrieving statistics on a VM. For more information, see Java statistics monitoring tool.
-XX:+TransparentHugePage is enabled by default on more Linux systems
-XX:+TransparentHugePage is enabled by default on Linux® systems for POWER and IBM Z as well as x86 systems. This option takes affect only when Transparent Huge Pages (THP) is set to
madvise on your system. When transparent Huge Pages are used, your application footprint might increase.
Add new Xdump exit agent and ExitOnOutOfMemoryError option
The new Xdump agent "exit" shuts down the VM when the specified event occurs. The "exit" agent is at priority level 0 and "tool" agent has been moved to priority level 1 to aid in mimicking the behavior of HotSpot options. See Xdump dump agents for more about agents.
OpenJ9 now supports the HotSpot option
-XX:[+-]ExitOnOutOfMemoryError. You can set this option to have the VM shut down when a java.lang.OutOfMemory error is thrown by the VM or in Java code. See the -XX:[+-]ExitOnOutOfMemoryError option.
The Xdump "exit" agent is used in the implementation of
LUDCL caching enabled by default
By caching the Latest User Defined Class Loader (LUDCL), Java applications that use deserialization extensively can see a performance improvement. This capability is controlled by the -Dcom.ibm.enableClassCaching system property and is now enabled by default. This feature was disabled for the 0.17.0 release due to issue #7332 which has now been resolved.
Terabytes suffix support for -X and -XX options that take a size
OpenJ9 now supports 't' and 'T' suffixes (indicating terabytes) for -X and -XX options that take a
Improved support for pause-less garbage collection
Support for Concurrent scavenge mode is now extended to macOS®. For more information, see
The previously undocumented option
-Xgc:noConcurrentScavenge disables pause-less garbage collection.
Add more changes here...
Full release information
To see a complete list of changes between Eclipse OpenJ9 v 0.17.0 and v 0.18.0 releases, see the Release notes.