Hi, first of all, thanks for reading this!

 

When trying to launch forge from a fresh install (installed using the installer) on Windows 10 64-bit, I get the following error: 

 

Spoiler

PS C:\Users\username\Documents\forge> java -Xmx2048M -Xms1024M -jar .\forge-1.12.2-14.23.2.2612-universal.jar
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(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.base/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.ClassCastException: java.base/jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to java.base/java.net.URLClassLoader
        at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
        ... 6 more

I've tried using both Java 8 and Java 9, but get the exact same error. I've also tried versions 14.23.2.2612 and 14.23.1.2555 and still get the exact same error. There are no mods installed yet, the mods folder is empty. I've tried deleting all files in the folder and starting fresh, same thing. I've tried running as an administrator, same thing. I've tried launching the regular minecraft jar first, agreeing to the eula, and then launching the forge jar: same thing. I've searched around for people with the same error, but haven't been able to find any useful information. No log files are generated. I've also checked the "Common Problems and Solutions" thread, but couldn't find any relevant help.

 

Any help here is greatly appreciated!!

 

Thanks, 

Bubblesses

Edited February 6, 20187 yr by bubblesses

26 minutes ago, bubblesses said:

I've tried using both Java 8 and Java 9, but get the exact same error.

Considering that this is a problem with Java 9 and literally impossible to get on Java 8, you need to try again.

Use Java 8.

Okay, I'll give it another go!

This worked for me, thanks!

I have been the same problem, i start mine forge.jar and not is happenning. I have installed the java 8; 

I trying to run a 1.12.2 server forge

1.12 is no longer supported on this forum.
Please update to a modern version of Minecraft to receive support.