Was testing in a virtual box environment the the upgrade of Ubuntu with:
do-release-upgrade
I had Java 8 before upgrade. It was replaced with the default openjdk7 after the upgrade. Java 8 was still installed just had to make it the default again. Just thought I would throw this out there in case it may help someone.
If you install:
oracle-java8-set-default
it will set 8 back to default.