The instructions on this page for the installs are incorrect:
These 2 lines:
sudo apt-get update && sudo apt-get install openhab sudo apt-get install openhab-addons
Should be changed to openhab2:
sudo apt-get update && sudo apt-get install openhab2 sudo apt-get install openhab2-addons
It will not work because you will be installing Zulu version 8 and then installing Openhab 3 instead of Openhab 2.
The pages for other operating systems are incorrect as well.