should move Dockerfile from installing Oracle JDK to Zulu OpenJDK

[jwhowarth]

The Oracle JDK license is now very restrictive. Replacing Oracle JDK with Zulu OpenJDK seems to be the best option.

https://www.azul.com/downloads/zulu/

On ubuntu this can be achieved with...

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0xB1998361219BD9C9
sudo apt-add-repository 'deb http://repos.azulsystems.com/ubuntu stable main'
sudo apt-get install zulu-8

The Zulu packaging of OpenJDK apparently is more extensive and includes the necessary NetBeans support for glassfish.

[superleah]

Oka/