Exception in thread "AWT-EventQueue-0" java.awt.HeadlessException:

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Ashok
Posts: 18
Joined: 01 Dec 2021, 08:40

Exception in thread "AWT-EventQueue-0" java.awt.HeadlessException:

Post by Ashok »

Hi,
I installed OpenWebStart on RHEL8.5 forcefully by using "rpm -ivh --nodeps openwebstart-1.3.3-2.x86_64.rpm". After installation, if I give "itw-settings", am ending with below error,
[root@devcl1 ~]# itw-settings
Exception in thread "AWT-EventQueue-0" java.awt.HeadlessException:
No X11 DISPLAY variable was set, but this program performed an operation which requires it.
at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:204)
at java.awt.Window.<init>(Window.java:536)
at java.awt.Frame.<init>(Frame.java:420)
at java.awt.Frame.<init>(Frame.java:385)
at javax.swing.JFrame.<init>(JFrame.java:189)
at net.adoptopenjdk.icedteaweb.client.controlpanel.ControlPanel.<init>(ControlPanel.java:88)
at com.openwebstart.launcher.ControlPanelLauncher.lambda$main$2(ControlPanelLauncher.java:81)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomai n.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
[root@devcl1 ~]#
Please check it and let me know the fix.

Janak Mulani
Posts: 497
Joined: 24 Mar 2020, 13:37

Re: Exception in thread "AWT-EventQueue-0" java.awt.HeadlessException:

Post by Janak Mulani »

itw-settings is a simple Java Swing based app.

You should set up your display properly to be able to run a Java Swing app.

It seems that Swing is not finding a display and thus giving HeadlessException.

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