Just a quick post here about java jvm choices so we have it easily searchable.
It seems that the oracle jvm has become increasingly difficult to use, particularly in automated setups. See https://launchpad.net/~webupd8team/+archive/ubuntu/java.
My understanding is that there are no significant drawbacks in using the openjdk runtime. So the ubuntu package I am using for installations on ubuntu 18.04 bionic is openjdk-8-jre headless.
Note that there are currently issues running DHIS2 against higher java versions (eg 9 and 11) so it is a good idea to install the runtime first, before installing things like tomcat8 which could pull in an incompatible jvm as a dependency.
I welcome any thoughts on different jvms people might be using and why.