What's new in version 0.18.1

The following new features and notable changes since version 0.17.0 are included in this release:

Features and changes

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.

-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.

New exit dump agent and ExitOnOutOfMemoryError option

The new exit dump agent shuts down the VM when the specified event occurs. The exit agent is at priority level 0 and the tool agent has been moved to priority level 1 to aid in mimicking the behavior of HotSpot options. For more information about dump agents, see -Xdump.

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 <size> parameter.

-Xgc:noConcurrentScavenge option

The previously undocumented option -Xgc:noConcurrentScavenge disables pause-less garbage collection.

Support for OpenJDK HotSpot options

For compatibility, the following OpenJDK HotSpot options are now supported by OpenJ9:

-Djava.lang.string.substring.nocopy option

The previously undocumented Java 8 option -Djava.lang.string.substring.nocopy=true avoids String sharing by String.substring(), which is the same behavior as the Oracle HotSpot VM.