[enhancement] Project workflow supports Java21

[TreasureJade]

Hello everyone, I recently upgraded the JDK version of the jcommon module from JDK20 to JDK21, and have successfully compiled it locally. However, our current project's workflow does not support JDK21, and as a result, the code I submitted is unable to pass the code check. Moving forward, I plan to add a JDK21 compilation workflow to the jcommon module. :)

This is the issue for the pull request of the JDK21 upgrade: #734