Install DSpace 6.x on Debian 9 (Stretch)

Installation of prerequisite applications
Open  Applications > Accessories > Terminal and execute the following commands. Apply following commands,

sudo apt update
sudo apt upgrade
sudo apt install leafpad openjdk-8-jdk ant maven postgresql

Install DSpace 6.x on Ubuntu 16.04 LTS

Installation of prerequisite applications
Open  Applications > Accessories > Terminal and execute the following commands. Apply following commands,

sudo apt update
sudo apt upgrade
sudo apt install leafpad openjdk-8-jdk ant maven