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# Eclipse OpenJ9 version 0.12.0 release notes

These release notes support the [Eclipse OpenJ9 0.12.0 release plan](https://projects.eclipse.org/projects/technology.openj9/releases/0.12.0/plan).


## Binaries and supported environments

OpenJ9 release 0.12.0 supports OpenJDK 8 and OpenJDK 11. Binaries are available at the AdoptOpenJDK project:

- [OpenJDK with OpenJ9 version 8](https://adoptopenjdk.net/archive.html?variant=openjdk8&jvmVariant=openj9)
- [OpenJDK with OpenJ9 version 11](https://adoptopenjdk.net/archive.html?variant=openjdk11&jvmVariant=openj9)

This release includes support for macOS&reg; on OpenJDK 8 with OpenJ9. Platform support for macOS is now available on OpenJDK 8 and OpenJDK 11 binaries that contain the OpenJ9 VM.

All builds are tested against the OpenJ9 functional verification (FV) test suite, the OpenJDK test suites, and additional tests at AdoptOpenJDK.

To learn more about support for OpenJ9 releases, including OpenJDK levels and platform support, see [Supported environments](https://eclipse.org/openj9/docs/openj9_support/index.html).


## Notable changes in this release

The following table covers notable changes in v0.12.0. Further information about these changes can be found in the [user documentation](https://www.eclipse.org/openj9/docs/version0.12/).

<table cellpadding="4" cellspacing="0" summary="" width="100%" rules="all" frame="border" border="1"><thead align="left">
<tr valign="bottom">
<th valign="bottom">Issue number</th>
<th valign="bottom">Description</th>
<th valign="bottom">Version / Platform</th>
<th valign="bottom">Impact</th>
</tr>
</thead>
<tbody>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/pull/3446">#3446</a></td>
<td valign="top">Improved flexibility for managing the size of the JIT code cache</td>
<td valign="top">OpenJDK8 and later (All platforms)</td>
<td valign="top">The size of the JIT code cache (-Xcodecachetotal) can now be decreased as well as increased, with a minimum size of 2 MB</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/pull/3992">#3992</a></td>
<td valign="top">OpenSSL is now supported for OpenJDK 11 to improve native cryptographic performance </td>
<td valign="top">OpenJDK11 (All platforms)</td>
<td valign="top">The OpenSSL V1.1.x implementation is enabled by default and supported for the Digest, CBC, and GCM algorithms. </td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/3478">#3478</a></td>
<td valign="top">New environment variable OPENJ9_JAVA_OPTIONS</td>
<td valign="top">OpenJDK8 and later (Linux)</td>
<td valign="top">This environment variable replaces the IBM_JAVA_OPTIONS variable, whis is now deprecated and will be removed from a future release. </td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/3338">#3338</a></td>
<td valign="top">Concurrent scavenge mode is now available on Linux x86 for large heap applications</td>
<td valign="top">OpenJDK8 and later (x86-64: Linux only)</td>
<td valign="top">When this mode is enabled, (`-Xgc:concurrentScavenge`) the VM attempts to reduce GC pause-times for response-time sensitive, large heap applications. This mode is now available on large heap (non-compressed references) builds. </td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/4108">#4108</a></td>
<td valign="top">Concurrent scavenge mode is now available on Windows x86</td>
<td valign="top">OpenJDK8 and later (x86-64: Windows only)</td>
<td valign="top">When this mode is enabled, (`-Xgc:concurrentScavenge`) the VM attempts to reduce GC pause-times for response-time sensitive applications. </td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/3226">#3226</a></td>
<td valign="top">Idle-tuning is enabled by default</td>
<td valign="top">OpenJDK8 and later (Linux only)</td>
<td valign="top">When OpenJ9 is running in a container, a garbage collection cycle and compaction of the object heap is attempted when
the state of the VM is set to idle. </td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/pull/4025">#4025</a></td>
<td valign="top">Changes to the default permissions of shared classes cache directories</td>
<td valign="top">OpenJDK8 and later (All platforms except Windows)</td>
<td valign="top">Tighter restrictions are imposed on existing and new shared classes cache directories. For further
information about this change, see the <a href="https://www.eclipse.org/openj9/docs/version0.12/">user documentation</a>.</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/3636">#3636</a></td>
<td valign="top">OpenSSL V1.1 support for the RSA algorithm</td>
<td valign="top">OpenJDK8 and later (All platforms except AIX)</td>
<td valign="top">OpenSSL 1.1.x support is now available for the RSA algorithm, in addition to Digest, CBC, and GCM.</a></td>
</tr>

</table>


## Known Issues

The v0.12.0 release contains the following known issues and limitations:

<table cellpadding="4" cellspacing="0" summary="" width="100%" rules="all" frame="border" border="1">
<thead align="left">
<tr valign="bottom">
<th valign="bottom">Issue number</th>
<th valign="bottom">Description</th>
<th valign="bottom">Platform</th>
<th valign="bottom">Impact</th>
<th valign="bottom">Workaround</th>
</tr>
</thead>
<tbody>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/3483">#3483</a></td>
<td valign="top">DDR support</td>
<td valign="top">macOS</td>
<td valign="top">Inability to diagnose problems with the VM, garbage collector, or JIT.</td>
<td valign="top">None</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/4222">#4222</a></td>
<td valign="top">Shared classes no longer enabled by default</td>
<td valign="top">All platforms</td>
<td valign="top">In milestone 1, shared classes were enabled by default. This change has been reverted due to a performance regression.</td>
<td valign="top">None</td>
</tr>

<tr><td valign="top"><a href="https://github.com/ibmruntimes/openj9-openjdk-jdk8/issues/129">#129</a></td>
<td valign="top">OpenSSL support</td>
<td valign="top">AIX</td>
<td valign="top">Bundling OpenSSL on AIX can result in problems like https://github.com/ibmruntimes/openj9-openjdk-jdk8/issues/129.</td>
<td valign="top">None</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/54">#54</a></td>
<td valign="top">Signal handling</td>
<td valign="top">All platforms</td>
<td valign="top">Currently, shutdown signals (<code>SIGINT</code>, <code>SIGHUP</code> and <code>SIGTERM</code>) and <code>SIGCONT</code> are fully supported on Unix platforms (pLinux, zLinux, xLinux, AIX, and z/OS). Support for other POSIX signals is pending. See <code>SunMiscSignalTest.java</code> for the list of signals that need to be supported.</td>
<td valign="top">None</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/2507">#2507</a></td>
<td valign="top">Restriction analyzing system (core) dumps</td>
<td valign="top">Linux and Windows</td>
<td valign="top">You must use a 32-bit JVM to look at a 32-bit core, and a 64-bit JVM to look at a 64-bit core. This restriction will be fixed in a later version of OpenJ9.</td>
<td valign="top">None</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/479">#479</a></td>
<td valign="top">Non-compressed references VM builds not available</td>
<td valign="top">AIX, Windows, Linux on Z, Linux on Power</td>
<td valign="top">Non-compressed references VM builds, which support heaps larger than 57GB, are built on Linux on x86. </td>
<td valign="top">Manual builds on other platforms are possible by following our <a href="https://github.com/eclipse-openj9/openj9/blob/master/buildenv/Build_Instructions_V8.md">detailed build instructions</a>.</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/897">#897</a></td>
<td valign="top">Javadoc not building some OpenJ9 extensions.</td>
<td valign="top">All platforms</td>
<td valign="top">Some API documentation is missing in the <code>build/&lt;platform&gt;/docs</code> directory.</td>
<td valign="top">None</td>
</tr>

<tr><td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/898">#898</a></td>
<td valign="top">Javadoc building some unsupported OpenJ9 extensions.</td>
<td valign="top">All platforms</td>
<td valign="top">Some API documentation in <code>build/&lt;platform&gt;/docs</code> is not supported with OpenJ9.</td>
<td valign="top">None</td>
</tr>

</tbody>
</table>

## Other changes

A full commit history for this release is available at [Eclipse OpenJ9 v0.12.0](https://github.com/eclipse-openj9/openj9/releases/tag/openj9-0.12.0).
