I'm trying to set up a modpack server and haven't been able to find good information on how to do so. It seems like it's mostly spread by word of mouth or through transient forum threads. Here's my repro case on Windows 10:

 

- Install Java SE runtime 1.8.0_181

- Download minecraft 1.12.2 server.jar into a new folder

- Download recommended Windows installer (1.12.2 - 14.23.4.2705) and do the "server" install into the same folder. In creates a couple .jar's in the root and a libraries folder

- Open cmd in administrator mode

 

C:\myFolder>java -jar forge-1.12.2-14.23.4.2705-universal.jar
A problem occurred running the Server launcher.java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:62)
        at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:31)
Caused by: java.lang.NoClassDefFoundError: org/apache/logging/log4j/Level
        at net.minecraft.launchwrapper.Launch.launch(Launch.java:94)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
        ... 6 more
Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.Level
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        ... 8 more

 

This is a simple example with no flags, but I've tried messing with flags like RAM allocation and nogui, but it always immediately dies with the above error. I've also tried launching the vanilla server first just in case forge needs some files initialized, and that didn't help either.

 

What am I doing wrong?

29 minutes ago, jj10dman said:

Download recommended Windows installer

Don't use the Windows installer, use the jar one.

 

Thanks so much, that got me unstuck for now. Out of curiosity why is the Windows installer so prominent if it doesn't work for this purpose?

9 minutes ago, jj10dman said:

Out of curiosity why is the Windows installer so prominent if it doesn't work for this purpose?

I've got no idea, maybe @diesieben07 could shine more light on this.