Solved Starting FTB Revelation server on linux returns an error

[ChigBungus]

I have successfully started a vanilla minecraft server on the system but for some reason when i try running Revelation it returns this error:

A problem occurred running the Server launcher.java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:70)
at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:34)
Caused by: java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')
at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
... 6 more


The error occurs right after I agree to the eula.
The problem probably has something to do with java. I have already tried the newest versions of both openjdk and oracle jdk, so I'm at a loss here.

 

[ChigBungus]

I managed to solve the issue.
For anyone with the same problem here is my solution:
- Remove java. I used this tutorial. https://novicestuffs.wordpress.com/2017/04/25/how-to-uninstall-java-from-linux/
- Install openjdk 8 java. Use this command: sudo apt install openjdk-8-jre-headless