What's new in version 0.24.0

The following new features and notable changes since version 0.23.0 are included in this release:

• Changes to message logging
• -XX:[+|-]PortableSharedCache option support update
• Change in behavior for the jextract utility
• New diagnostic suboption for -Xcheck:jni for fatal JNI errors

Features and changes

Changes to message logging

JEP 158 introduces the -Xlog option as a common logging system for all components of a Java virtual machine. To avoid confusion with the reference implementation, the -Xsyslog option replaces the existing OpenJ9 -Xlog option for message logging. For compatibility with the reference implementation, a limited set of -Xlog suboptions are supported.

A new option, -XX:[+|-]LegacyXlogOption, controls how -Xlog is processed when set on the command line.

• When -XX:-LegacyXlogOption is set, the -Xlog option is recognized when a form of this option runs that requests garbage collection (GC) logging.
  • If any -Xlog GC log requests are set, these options are mapped to the equivalent OpenJ9 verbose GC command line options. For more information, see -Xlog.
• Setting -XX:+LegacyXLogOption provides backward compatibility with the legacy -Xlog option, which can be specified on the command line with the parameters documented for the -Xsyslog option. That is, these options can be used interchangeably.

-XX:[+|-]PortableSharedCache option support update

The -XX:[+|-]PortableSharedCache option is now supported on IBM Z® and POWER® platforms. AOT-compiled code that is generated with this option is guaranteed to be portable across IBM z10 or newer microarchitectures on IBM Z platforms and IBM POWER8® or newer microarchitectures on POWER platforms. See -XX:[+|-]PortableSharedCache for more details about this option.

Change in behavior for the jextract utility

The jextract utility gathers relevant files following a system dump to assist with problem determination. It is important that the jextract utility is run from the same SDK that generated the dump. From this release, if the build ID of the jextract utility does not match the build ID of the SDK that is recorded in the system dump, an exception message is generated. To force jextract to continue, a new option, -r, is introduced. For more information, see Dump extractor.

New diagnostic suboption for -Xcheck:jni for fatal JNI errors

A new abortonerror suboption for -Xcheck:jni provides diagnostic data when fatal JNI errors occur. For more information, run -Xcheck:jni:help.