No X11 DISPLAY variable was set,
or no headful library support was found,
but this program performed an operation which requires it,
at java.desktop/java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:164)
at java.desktop/java.awt.Window.init(Window.java:501)
at java.desktop/java.awt.Window.<init>(Window.java:453)
at java.desktop/java.awt.Window.<init>(Window.java:608)
at java.desktop/java.awt.Dialog.<init>(Dialog.java:674)
at java.desktop/java.awt.Dialog.<init>(Dialog.java:519)
at java.desktop/javax.swing.JDialog.<init>(JDialog.java:426)
at java.desktop/javax.swing.JOptionPane.createDialog(JOptionPane.java:957)
at de.uwemock.eur.gui.start.Startup.askForAutomaticUpdateCheck(Startup.java:90)
at de.uwemock.eur.gui.start.Jes.main(Jes.java:49)