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# Eclipse OpenJ9 version 0.45.0 release notes

These release notes support the [Eclipse OpenJ9&trade; 0.45.0 release plan](https://projects.eclipse.org/projects/technology.openj9/releases/0.45.0/plan).

## Supported environments

OpenJ9 release 0.45.0 supports OpenJDK 22.

All releases are tested against the OpenJ9 functional verification (FV) test suite, the OpenJDK test suites, and additional tests provided by Adoptium.

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

There are no additional issues or features specific to v0.45.0. All the issues or features in v0.44.0 release are available in v0.45.0. Information about the changes in v0.44.0 can be found in the [user documentation](https://www.eclipse.org/openj9/docs/version0.44/).

## Known issues

The v0.45.0 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>
<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/15011">#15011</a></td>
<td valign="top">The default stack size for the main thread is a smaller platform-dependent value.</td>
<td valign="top">All</td>
<td valign="top">The main thread stack size was 1 MB in releases before 0.32. In the 0.32 release and later it was modified to a smaller
platform-dependent value, the same value as the <tt>-Xmso</tt> setting. The 0.33 release increased the default <tt>-Xmso</tt> stack size
on x64 platforms, but builds with OpenJDK 17 and later also require more stack space to run. These changes might result in a
<tt>java.lang.StackOverflowError: operating system stack overflow</tt>.</td>
<td valign="top">Use <tt>-Xmso</tt> to set the default stack size. See the default value by using <tt>-verbose:sizes</tt>.</td>
</tr>

<tr>
<td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/13767">#13767</a></td>
<td valign="top">Compressed references mode is not available.</td>
<td valign="top">Apple silicon macOS</td>
<td valign="top">You can use only the large heap (non-compressed references) mode.</td>
<td valign="top">None</td>
</tr>

<tr>
<td valign="top"><a href="https://github.com/eclipse-openj9/openj9/issues/14803">#14803</a></td>
<td valign="top">Using the <tt>-XX:+ShowHiddenFrames</tt> option in an OpenJ9 release that is built with OpenJDK 18 and later causes errors.</td>
<td valign="top">All platforms</td>
<td valign="top">Wrong exception might be thrown when using the Reflection API.</td>
<td valign="top">Avoid using the <tt>-XX:+ShowHiddenFrames</tt> option with OpenJDK 18 and later.</td>
</tr>

</tbody>
</table>

## Other changes

A full commit history for 0.45.0 release is available at [Eclipse OpenJ9 v0.45.0](https://github.com/eclipse-openj9/openj9/releases/tag/openj9-0.45.0).
