install from repo on Ubuntu 16.04 is broken

Installing XWIKI 9.7 on a newly created Ubuntu (Server) 16.04.2 + dist-upgrade (@ 2017-09-24) using the proposed method fails:

wget -q "http://maven.xwiki.org/public.gpg" -O- | sudo apt-key add -
wget "http://maven.xwiki.org/stable/xwiki-stable.list" -P /etc/apt/sources.list.d/

#update sources
apt-get update
#install from sources
apt-get install -y xwiki-tomcat8-pgsql

Errors:
1.) The dependencies include JAVA resolving during the install process will install JAVA 9 -> known not to work with tomcat. As a result tomcat fails to start.

2.) Manually installing JAVA 8 prior to XWIKI will prevent the JAVA 9 installation. tomcat starts but starting XWIKI on tomcat fails to create a working XWIKI server.

Info:
Because the manual install requires advanced Linux/tomcat knowledge I set the issue's priority (for the install) on "Blocker", especially since the problematic method is the recommended install method on Ubuntu.
Manually installing JAVA 8, tomcat 8.5.20, postgresql 9.5 and deploying XWIKI using a war file works fine.