NoClassDefFoundError

[gaussandhisgun]

Не может найти какой-то класс. Ubuntu 18.04.5 LTS, Java 11 и Java 8 выдают одну и ту же ошибку, JavaFX установлен: openjfx/bionic-updates,bionic-security,now 11.0.2+1-1~18.04.2 i386 [установлен]

Сама ошибка:

gravitos@gravitos-rootbox:~$ java -jar ./ImageConverter.jar 
Error: Could not find or load main class sample.Main
Caused by: java.lang.NoClassDefFoundError: javafx/application/Application

[Gladox114]

I have no clue what's the exact problem but I think javafx is missing in the open version of java (openjdk) or something is broken because I get the same error on Manjaro with openjdk-11 and also tried openjdk-8 with a different error
Error: Could not find or load main class sample.Main
At the end I found out that it works with Oracle java so you need java-8-jre from oracle.

For Arch users install this: https://aur.archlinux.org/packages/jre8
Not sure how to install Oracle java 8 on Ubuntu but maybe this tutorial could help.
If you installed original Minecraft then you probably get a runtime included somewhere in the files of Minecraft. You can use that instead. Just go into the settings and maybe the launcher even tells you where it's saved. I don't know this because I use MultiMC

[Namelessys]

That fixed the problem for me. Thx!