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What's new in version 0.40.0

The following new features and notable changes since version 0.39.0 are included in this release:

Features and changes

Binaries and supported environments

Eclipse OpenJ9™ release 0.40.0 supports OpenJDK 8, 11, 17 and 20.

To learn more about support for OpenJ9 releases, including OpenJDK levels and platform support, see Supported environments.

New -XX:codecachetotalMaxRAMPercentage option added

In environments with low physical memory availability, the VM might use too much memory for JIT code caches, leaving little memory for critical operations. With the -XX:codecachetotalMaxRAMPercentage option, you can set an upper limit for the total code cache size, where the upper limit is specified as a percentage of the physical memory the VM process is allowed to use.

For more information, see -XX:codecachetotalMaxRAMPercentage.

VM starts with a warning message after the container detection fails

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 file system. In previous releases, the VM exits when it encounters this scenario. From this release, the VM starts with a warning message after the container detection fails.

For more information, see the Cloud optimizations topic.

Support for persistent shared classes cache added on z/OS

Persistent shared caches are now supported on z/OS systems. The default cache type on z/OS is still non-persistent. You can use the -Xshareclasses:persistent option to switch to persistent shared cache.

EC key generation algorithm and XDH key agreement and generation algorithms support for OpenSSL

The EC key generation algorithm can now use the native OpenSSL library for all OpenJDK versions.Start of content that applies to Java 11 (LTS) and later The XDH key agreement and generation algorithms can also use the native OpenSSL library.End of content that applies to Java 11 (LTS) and later For more information, see -Djdk.nativeECKeyGen, -Djdk.nativeXDHKeyAgreement, and -Djdk.nativeXDHKeyGen.

Known problems and full release information

To see known problems and a complete list of changes between Eclipse OpenJ9 v0.39.0 and v0.40.0 releases, see the Release notes.