Java GUI Maven Project in Docker with X11 Error

Question

I have a JavaFX Maven Project. Run I run the Jar file, a GUI pops open for the user. I am trying to run it from a Docker container. I'm using Ubuntu 16.04.

I keep getting this error:

Exception in thread "AWT-EventQueue-0" java.awt.HeadlessException: No X11 DISPLAY variable was set, but this program performed an operation which requires it.

Here is my Docker file (using a solution from here).

FROM docker.io/java as firstStage
WORKDIR /workdir/
RUN /usr/sbin/useradd --comment Developer \
                  --home-dir /home/developer \
                  --non-unique --uid 1000 --user-group --system \
                  --shell /bin/bash developer && mkdir -p /home/developer

RUN chown -R developer:developer /home/developer && mkdir -p /opt/app && chown -R developer:developer /opt/app

RUN echo 'developer ALL=(ALL) NOPASSWD: ALL' >> /etc/sudoers
USER developer
ENV HOME /home/developer
VOLUME /opt/app

FROM maven:3.5.0-jdk-8
COPY --from=firstStage /workdir/ .
COPY . /
RUN apt-get update && apt-get install -y --no-install-recommends openjfx && rm -rf /var/lib/apt/lists/* && mvn clean install && DISPLAY=localhost:0.0

CMD ["java","-jar","/target/CodeDemo-1.0-SNAPSHOT.jar"]

I've looked through plenty of other answers to this question, and here is what else I've tried:
Running CMD with -Djava.awt.headless=true.

Trying the SO solution here where you run "xauth add" within the container. But xauth "is not found". So I tried adding RUN sudo apt-get install xauth to the Dockerfile. When I tried to build, I got an error saying xauth wasn't found. I did the same thing with x11-apps.

I thought maybe it wouldn't install because it couldn't be found on my host machine (just a random guess), but I can run xauth on my host machine.

The only other solutions I've seen involved Putty and ssh. I just want to run the Docker container on my computer, not ssh into another one. I also saw some answers about virtualization. Do I have to create a whole virtual machine to run one program? Or am I missing something?

Anyone have any suggestions?

Some inspiration maybe: read [this](http://fabiorehm.com/blog/2014/09/11/running-gui-apps-with-docker/) — Federico klez Culloca, Feb 07 '19 at 13:25
This seems a great challenge, not sure if you could run desktop GUI applications without virtualizing the whole target OS. Good luck and let us know. — Aritz, Feb 07 '19 at 13:28
Thank you both. I was thinking this may not be as straightforward as I thought, but I just got started with Docker and thought I was missing something simple. — JustBlossom, Feb 07 '19 at 13:34

score 1 · Answer 1 · answered Feb 09 '19 at 16:59

This is definitely possible. The given error message is actually quite good. You need to set X11 DISPLAY variable.

The solution to your problem could be as simple as adding

-e DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix

to your docker run command. You might need to run

sudo xhost +

before that, in order to allow connections to your host XServer.

You can also have a look at the following blog posts, who explain this in more detail:

If you also need actual graphics support, for e.g. OpenGL, have a look at https://github.com/NVIDIA/nvidia-docker.

Java GUI Maven Project in Docker with X11 Error

1 Answers1