Screen capture does not work with OpenJDK on Wayland

[RetGal]

Screen capture does not work on systems using Wayland display server in combination with OpenJDK.
(Which is the default on Debian Buster)

To Reproduce

1. Start Dayon Assisted within a session running with Wayland.
2. Connect to the Assistand running on whatever system.
3. Only a plain black screen is transmitted to the Assistant.

Workaround

• Use Oracle JDK/JRE instead
• Or start a X.Org server instead:
  Logout > see the login screen > click the gear icon > select Xorg > login again.

Affected:

• OS: Any linux using Wayland and OpenJDK (for example Debian 10 aka Buster)
• Version: Any

[idnovic]

read the comments here:
https://www.reddit.com/r/gnome/comments/frv4sf/conferencing_on_wayland/

I believe pipewire is needed

[RetGal]

@idnovic thanks for your input, i'll definitely have a closer look at it!

[RetGal]

@idnovic Unfortunately pipewire doesn't solve the problem. It's indeed a bug/missing feature of the OpenJDK, as with Oracles implementation the screen capturing on Wayland works as expected. It's a pity, that only OpenJDK developers are allowed to open issues/bugs on their project..

[idnovic]

okay I see. Is it working with adoptjdk?
https://adoptopenjdk.net/?variant=openjdk8&jvmVariant=openj9

[RetGal]

@idnovic
Thanks for your suggestion. I tested it with the LTS (OpenJDK11U-jdk_x64_linux_openj9_11.0.7_10) and with the latest version (OpenJDK14U-jdk_x64_linux_hotspot_14.0.1_7) but neither of them works. It's definitely an OpenJDK issue

[idnovic]

Is this still an issue? any news on this?

[RetGal]

Hi @idnovic
Yes, it's still an issue. I hope that one day the openJDK developers will finally fix their Wayland screen capture implementation :)

[Triloworld]

Maybe add upstream tag and workaround to show that error isn't relative to this project. We will wait more time on that issue on openJDK team ;/ Any mention tag available to show them where is problem?

@idnovic Unfortunately pipewire doesn't solve the problem. It's indeed a bug/missing feature of the OpenJDK, as with Oracles implementation the screen capturing on Wayland works as expected. It's a pity, that only OpenJDK developers are allowed to open issues/bugs on their project..

[RetGal]

Hooray! It looks like OpenJDK 21 will finally support screen capture on Wayland: bugs.openjdk.org/browse/JDK-8280982

[RetGal]

An update for the current state regarding the support of assisted computers with Wayland.

assisted computers using the Wayland display manager are only supported, if:

• Dayon! is installed as deb, tgz or as standalone assisted.sh or jar
• OpenJDK 21 or newer is present (or an Oracle JRE/JDK)

But if Dayon! is installed as snap or as flatpak, assisted using Wayland are currently not supported!

The only workaround for these cases is to switch the display manager to Xorg:
Logout > on the login screen click the gear icon > select Xorg > login again