>What if I am on the latest jre8 version when Java 9 is out, and I need to go
>back to an earlier version: then I need to track when the switch from
>unsuffixed Java 8 to suffixed Java 8 version occurred to be able to
>downgrade (granted, that is a bit less common scenario).
Frankly speaking, I do not get the use-case you are trying to convey.
Suppose you have x.y.z and that is the latest jre8 version at some
point in time.
Even after jre9 is launched, the same x.y.z will still be jre8.
So if you "do not want to upgrade", you just keep your version x.y.z.
If you want to upgrade (suppose, the most current version is "k.l.m"),
you just use k.l.m-jre8 if you a still stuck with jre8.
> What if I am on the latest jre8 version when Java 9 is out, and I need to go
> back to an earlier version
As I said above, I see no practical use case, except for some "bug
hunting via driver version bisection".
If that is the case, there is always list of all the versions:
https://jdbc.postgresql.org/download.html#others
Vladimir