Install JDownloader on Ubuntu Server 16.04

Install Java and get JDownloader with the following commands.

sudo apt install openjdk-8-jre-headless
wget http://installer.jdownloader.org/JDownloader.jar

After that move JDownloader.jar and change the owner to the user (e.g. media) under which JDownloader should be executed.

sudo mkdir /opt/jdownloader
sudo mv JDownloader.jar /opt/jdownloader
sudo chown media:media /opt/jdownloader 

Now we are ready to install JDownloader. Execute this command several times until you get asked for your My JDownloader login credentials on the console.

java -jar /opt/jdownloader/JDownloader.jar -norestart

Then create a new systemd unit under /etc/systemd/system/jdownloader.service and paste this script.

[Unit]
Description=JDownloader Service
After=network.target

[Service]
Environment=JD_HOME=/opt/jdownloader
Type=oneshot
ExecStart=/usr/bin/java -Djava.awt.headless=true -jar /opt/jdownloader/JDownloader.jar
RemainAfterExit=yes
# Should be owner of /opt/jdownloader
User=media
Group=media

[Install]
WantedBy=multi-user.target

To enable JDownloader on startup run this command.

sudo systemctl enable jdownloader.service

After a reboot you can access your server under https://my.jdownloader.org

Enjoy!