:~/Downloads$ java -jar graphwar.jar
Exception in thread "main" java.awt.HeadlessException
at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:207)
at java.awt.Window.<init>(Window.java:535)
at java.awt.Frame.<init>(Frame.java:420)
at java.awt.Frame.<init>(Frame.java:385)
at javax.swing.JFrame.<init>(JFrame.java:174)
at Graphwar.Graphwar.<init>(Graphwar.java:28)
at Graphwar.Graphwar.main(Graphwar.java:39)
:~/Downloads$ java -version
java version "1.7.0_79"
OpenJDK Runtime Environment (IcedTea 2.5.6) (7u79-2.5.6-0ubuntu1.15.04.1)
OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)
denis@woot:~/Downloads$ ^C
denis@woot:~/Downloads$ ^C
denis@woot:~/Downloads$