JabRef not opening on Ubuntu 18.04 after openjfx Update

The last system update seems to have introduced a openjfx update which prevents JabRef from opening (i guess). Clicking the icon does nothing (no error, no window opening and there seems no process running).

Trying to do java -jar JabRef-4.3.1.jar results in
Error: Could not find or load main class org.jabref.JabRefMain

java -v
openjdk version “1.8.0_191”
OpenJDK Runtime Environment (build 1.8.0_191-8u191-b12-2ubuntu0.18.04.1-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)

The update history:
Start-Date: 2019-04-17 11:35:02
Commandline: apt upgrade
Install: openjfx-source:amd64 (11.0.2+1-1~18.04.2, automatic)
default-jre-headless:amd64 (2:1.10-63ubuntu1~02, 2:1.11-68ubuntu1~18.04.1),
default-jdk:amd64 (2:1.10-63ubuntu1~02, 2:1.11-68ubuntu1~18.04.1),
default-jre:amd64 (2:1.10-63ubuntu1~02, 2:1.11-68ubuntu1~18.04.1),
openjdk-11-jre-headless:amd64 (10.0.2+13-1ubuntu0.18.04.4, 11.0.2+9-3ubuntu1~18.04.3),
libopenjfx-java:amd64 (8u161-b12-1ubuntu2, 11.0.2+1-1~18.04.2),
openjdk-11-jdk:amd64 (10.0.2+13-1ubuntu0.18.04.4, 11.0.2+9-3ubuntu1~18.04.3),
openjdk-11-jre:amd64 (10.0.2+13-1ubuntu0.18.04.4, 11.0.2+9-3ubuntu1~18.04.3),
libopenjfx-jni:amd64 (8u161-b12-1ubuntu2, 11.0.2+1-1~18.04.2),
default-jdk-headless:amd64 (2:1.10-63ubuntu1~02, 2:1.11-68ubuntu1~18.04.1),
libjavascriptcoregtk-4.0-18:amd64 (2.22.6-0ubuntu0.18.04.1, 2.24.1-0ubuntu0.18.04.1),
openjdk-11-jdk-headless:amd64 (10.0.2+13-1ubuntu0.18.04.4, 11.0.2+9-3ubuntu1~18.04.3), openjfx:amd64 (8u161-b12-1ubuntu2, 11.0.2+1-1~18.04.2),
java-common:amd64 (0.63ubuntu1~02, 0.68ubuntu1~18.04.1)

I removed everything from the excerpt that seemed unrelated.

Was it the upgrade or could it be something else changed? JabRef worked before, so it was all installed correctly and this seems to be the reason that is most likely.

To fix this, this GitHub Issue does the trick

Basically, downgrade the versions and mark them to hold and everything is fine