As far as I know and have googled on the Internet Java requires user input
to complete the update/installation, but does anyone know if this actually can be bypassed?
I have a computer for the public audience, not in a domain that needs to be able
to download and update silently. Normally we use SCCM, but not in this case.
But, I guess silent updating of Java is not yet been resolved or is it?

When it comes to Adobe Reader and Flash.
Does the silent updates trigger any feedback like pop-up balloon messages
or dialog windows I should know about.
Or is it truly set and forget?