Coverage chart / Java
Floodtide does not update Java
Java is a toolchain, not an app bundle. Rather than leave you to find that out after paying, here is the whole reason.
Why not
There is no Java.app for Floodtide to check a version against or swap. It installs as command line tools spread across the system, versioned by whichever manager put them there. Floodtide is an updater for applications, and stretching it to cover package managers would make it worse at the thing it is for.
brew upgrade, or whichever version manager you installed it with, is the right tool here.
Floodtide also reads the Sparkle feed of any installed app that publishes one, which is a separate path from the Homebrew list. If Java ships a Sparkle feed on your Mac, it will appear in your update list even though it is not on the coverage chart.
What this says about the rest
MacUpdater kept a hand-maintained database of every Mac app, which is why it could claim near total coverage right up until the day it could not maintain it any more. Floodtide reads sources the vendors already keep current, so the coverage list is smaller and it does not go stale. The trade is deliberate: a shorter list you can trust beats a longer one you cannot check.
Questions about Java
Does Floodtide update Java?
No. Java is a toolchain, not an app bundle. There is no Java.app for Floodtide to check a version against or swap. It installs as command line tools spread across the system, versioned by whichever manager put them there. Floodtide is an updater for applications, and stretching it to cover package managers would make it worse at the thing it is for.
Will Floodtide ever cover Java?
If the way Java is published changes so that a verifiable version becomes readable, it appears in the coverage list automatically. The list is rebuilt from the live source, so nothing has to be added by hand.
Does Floodtide hide apps it cannot update?
No. Floodtide shows an app it cannot handle with the reason attached, in the app and here. An updater that quietly omits what it cannot do is one you cannot use to answer the question "is this Mac up to date", which is the only question that matters.