Fail on RaspberryPi 4 (Unable to open DISPLAY) about liberica

[AlexanderScherbatiy]

Which way do you use to run JavaFX on Raspberry Pi?

I tried jdk16 arm32-vfp-hflt full version from bell-sw on Raspberry Pi 4 with Raspbian 10 (buster) with Raspberry Pi 7" Touch Screen Display.

I can run a JavaFX app directly attaching a mouse and a keyboard to Raspberry Pi and writing the command in a shell window which I opened in Raspbian desktop or connecting to Rasperry Pi via VNC.

java -version
openjdk version "16" 2021-03-16
OpenJDK Runtime Environment (build 16+36)
OpenJDK Server VM (build 16+36, mixed mode)

java HelloWorld

This works for me with Legacy GL driver. I used sudo raspi-config and the /boot/config.txt is

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
#dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d

and with GL (Fake KMS)

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
dtoverlay=vc4-fkms-v3d

If I connect to Raspberry Pi4 using ssh and run JavaFX I also see Unable to open DISPLAY exception. Running UI using ssh requires using '-X' option:

ssh -X pi@host
java HelloWorld

In this case I see the HelloWorld JavaFX app but it is shown not in Raspberry Pi but on my Linux system which I use to connect to Raspberry Pi.

[voitylov]

Closing as it seems to be a configuration issue.

[maebli]

We have the same issue in a project as stated by OP. What configuration resolves this issue?