Failed to execute the [groovy] macro error when creating an AWM on XWiki 14.10.19 using Java 21

Steps to reproduce

1. Start XWiki 14.10.19 (tested both on Jetty/HSQLDB and Tomcat 9.0.82) with Java 21 (I've used the one from Oracle)
2. Login as Admin
3. Click on 'More Applications > Create your own!'
4. Click 'Create Application' button
5. Fill in an app name
6. Click 'Next Step' button

Expected results

The user is advanced to Step 2 without any errors.

Actual results

On Step 2, there is the following error:

Failed to execute the [groovy] macro. Cause: [Unsupported class file major version 65]. Click on this message for details.

The issue seems to not reproduce on XWiki 15.5.3 or 15.19 with Java 21 and it also doesn't reproduce on any XWiki version with Java 17.