ColdFusion 2016 - Highest version of JDK is 12? Where is it on Oracle?

The confusion is understandable. I think I can offer an authoritative answer/explanation. First, let's talk about the current Java versions (at this writing) and CF's current support of them.

I'd assert you shouldn't use Java 13 currently with CF, as it's not yet supported yet by CF2016 or 2018. As for 13 and 12, these are what oracle regards as temporary releases (as were 9 and 10). Java 11 instead is termed a longterm release, as was 8. Both are still updated by Oracle, and CF2016 still supports either. So just use the latest of either 8 or 11. And cf2018 supports 10 (originally), 11 (as of update 2), or 12 (as of update 5), while CF2016 supports Java 8 (originally), 11 (as of update 8), and 12 (as of update 12).

Most folks on the latest versions of CF 2018 should for now use the latest update of Java 11, and folks on the latest version of CF2016 should for now use either the latest update of Java 8 or Java 11.

Adobe is offering support of the intermediate releases (9, 10, 12, etc.) along the way when they do so that those who WANT to use them for some reason can, but they have such short lives (months) that by the time they come out and Adobe gets them supported and releases a CF update for them, they will generally be ended by Oracle.

Again, the confusion is understandable, but this is a problem Oracle created, not Adobe. 

Finally, as for where to "get Java 12" if one really wanted it, as Kazu noted above, you can find downloads of the Java versions that Adobe DOES support at the bottom of the CF downloads page (not for downloading CF, but things RELATED to CF): https://www.adobe.com/support/coldfusion/downloads.html#additionalThirdPartyInstallers

https://www.adobe.com/support/coldfusion/downloads.html#additionalThirdPartyInstallers