Luke Plant

Thanks so much Fygul, this solved my problem.

Hm, looks like I actually have version 10, strange packaging thing - https://askubuntu.com/questions/1037646/why-is-openjdk-10-packaged-as-openjdk-11

I get the same message on Linux on startup, but I already have JRE 11 installed. At least, I have "openjdk-11-jre" installed, which is the latest version of openjdk available. If I run "java --version" I get: openjdk 10.0.2 2018-07-17 OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4) OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4, mixed mode)