Is not possible startup Jenkins in peace in Ubuntu Server. It for any:

• java                                          -jar jenkins.war --httpPort=9090
• java -Djava.awt.headless=true -jar jenkins.war --httpPort=9090

Even with:

• sudo apt install ttf-dejavu
• sudo apt install xvfb 

it according with:

• https://wiki.jenkins.io/display/JENKINS/Jenkins+got+java.awt.headless+problem

For more details please see the SO link.

Thank You.