I have just installed and re-installed forge-1.12.2-14.23.2.2611-universal into an empty folder using the installer and attempted to run it. Double-clicking gives me a brief second of appearance in task manager, and using a bat file gives me:

 

C:\Users\Kira\Desktop\Starland>java -Xmx1G -Xms1G -jar forge-1.12.2-14.23.2.2611-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
 

There is no log, no trace of it. Help?

Edited February 19, 20187 yr by Starboy47

Looks like a similar issue for a different user was solved by reinstalling java 8. Attempting this now.

Fixed it, thank you other person who made the same mistake!

Do you also have any more recent versions of java? I'm wanting to make sure I have an up-to-date java