Hello HomerJ,
Being that JAVA being installed is a prerequisite for the installation of ALM to occur and before it was never updatable, technically there are no step by step directions detailing the updating procedure for JAVA from Microfocus that I am aware of. The main issue to avoid as I see it will be if the server allows you to install a newer version with the old version running (I haven't tried so I can't say but don't think it does allow such things), so if it requires the old version to be uninstalled then you would have no version running and things would fail for the running of ALM.
As such, I would recommend scheduling a maintenance period and then stop the running ALM services, uninstall the old version (to avoid confusion in having multiple versions installed, and then installing the updated version build. You will need to then edit the Windows Environmental Variable, and restart the entire server (not just restart the services) to insure the new version is the only version running and you haven't just updated the JAVA but it made no changes to what the system is using (as with the Environmental VAriable in play it will cache that version and try to load it at start up (as the version build has the build version specified in the path so it wont find a JAVA version and start it if the path is not specified within the Environmental Variable for ALM to find it.
Here are some other JAVA references to help familiarize yourself with the JAVA installation and reference process:
https://eyeontesting.com/answers/does-updating-the-java-for-alm-require-a-restart-of-the-services/#answer-76392&gsc.tab=0
and
https://eyeontesting.com/answers/does-updating-the-java-for-alm-require-a-restart-of-the-services/#gsc.tab=0
Hope this helps,
Dan