We just merged pull request #7514 and Java 11 is now required to compile and deploy Dataverse from the "develop" branch.
The next version of Dataverse (whatever is after Dataverse 5.3) will include this update as well.
My upgrade experience was pretty smooth. I downloaded and installed Java 11 from
https://adoptopenjdk.net and my operating system (macOS) picked up the upgrade from Java 8 right away. To deploy I had to delete the Payara domain1 "generated" directory. I also had to restart Netbeans.
We wish you a smooth upgrade as well. If you have any trouble, just let us know.
Thanks,
Phil