No X11 DISPLAY variable was set

Ask Fedora
,
1

I set up a new laptop and I’m having an issue with Java wanting to use X11 but I don’t have whatever package I need to make the display work. Can anyone point me to how to fix this?

Sun Jan 18 11:31:52 EST 2026: loading core GUI class....
Sun Jan 18 11:31:52 EST 2026: YAAC raising splash screen....
java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:119)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at org.ka2ddo.yaac.YAAC.main(YAAC.java:791)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at org.ka2ddo.yaac.bootstrap.YAACBootstrap.main(YAACBootstrap.java:271)
Caused by: 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.

3

Can you verify which java you have installed?
dnf list --installed java*
if you just have the headless version installed can you install the full version?

4

Which desktop software did you install?
With gnome and kde plasma DISPLAY is setup by default.
You check that in a terminal by doing echo $DISPLAY.

5

$ dnf list --installed java*
Installed packages
java-25-openjdk-crypto-adapter.x86_64 1:25.0.1.0.8-3.fc43 updates
java-25-openjdk-headless.x86_64 1:25.0.1.0.8-3.fc43 updates
java-srpm-macros.noarch 1-7.fc43 fedora
javapackages-filesystem.noarch 6.4.1-4.fc43 koji-override-0
javapackages-tools.noarch 6.4.1-4.fc43 fedora
javascriptcoregtk4.1.x86_64 2.50.4-1.fc43 updates
javascriptcoregtk6.0.x86_64 2.50.4-1.fc43 updates

6

I’m running Cinnamon (GNOME?).

$ echo $DISPLAY
:0

7

I just installed java-25-openjdk and it seems to work. Odd, I could have sworn that I had that installed. :thinking:

I’ll continue testing and will report back, but I think it’s working now. Thank you!

1 Like
8

Okay, DISPLAY is set for tour login session.
Are you trying to run the java as a systemd service?

9

No, I’m just executing the .jar from the command line.