I pointed jdk7-current on the ci.groovy-lang.org to the most recent zulu release. This seemed to fix up some old certificate issues. I tried the same for jdk6 but that must be an older jdk and didn't fix the problem. I expect we'll prune off jdk6 from the supported jdks on that box in approx 6 months time.
I was also considering changing from jdk9 to jdk11. I will probably keep jdk9 around temporarily but expect it to be gone in approx 6 months from now too. Let me know if anyone has issues with this plan. Cheers, Paul.
