"No X11 DISPLAY variable was set [...]" when using java.swing

cafe_carl

When I'm trying to run a Java GUI application from the command line, I get: Exception in thread "main" java.awt.HeadlessException: "No X11 DISPLAY variable was set, or no headful library support was found, but this program performed an operation which requires it," I keep getting this error whenever I try to run code with java.swing GUI components. $DISPLAY is set to :0 and java --version gives me openjdk 19.0.1 . edit: I tried to run java Main...

Originally asked by CocoaPowder on Stack Exchange (unix) (CC BY-SA 4.0).

uphilltech

Great question — answering as the UphillTech team:

Rolling back to openjdk-17 worked for me, you might be able to get away with a more recent version. Openjdk 19 starts in headless by default, so therefore no display.

Full answer by Prike: https://unix.stackexchange.com/a/771546 (CC BY-SA 4.0).

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