Startup Issue with Minecraft - server not starting with forge

[Ale_Manno]

System Information

Field	Value
Operating System	Linux - Debian GNU/Linux 12 on x86_64
Product	AMP ‘Callisto’ v2.5.0.14 (Mainline)
Virtualization	Docker
Application	Minecraft
Module	MinecraftModule
Running in Container	Yes
Current State	Failed

Problem Description

Issue

A problem occurred running the Server launcher.java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:109)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
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.(Launch.java:34)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
… 3 more

Reproduction Steps

• installing forge 1.12.2 last version
• starting server
• server not starting

[ThePotatoKing]

Forge 1.12.2 needs Java 8

[Ale_Manno]

hey thanks for your response, done that and now it works but i wanted to install some mods but after creating a foulder and put there a modpack the server still seems on vanilla, any advice?

[ThePotatoKing]

You need to select the modloader and version in AMP (leave the jar as autoselect)