Is the openjdk-r ppa trustworty?

Solution 1:

Yes, it is trustworthy.

The PPA is run by Matthias Klose (Member of Ubuntu, Canonical Partner Developer, Gnome3 Team, Edubuntu developer, Xubuntu developer, ...) .

References :

Matthias Klose Profile on lauchpad
Debian's packages overview for Matthias Klose

Solution 2:

I have used it in the past, but openjdk site does not refer to it (that I can tell). The administrator of that ppa group is a member of many other groups including "Canonical Partner Developers”. If Canonical trusts him than I don't see a problem. His name (according to his launchpad profile) is Matthias Klose.