I need help adding more ram to my forge 1.12.2 server.

[kp11kp]

When I try and add more ram it wont work I tried to search it up but that don't help this is what it says when I launch it.


 

C:\Users\kp\OneDrive\Desktop\Server (moded)>java -Xmx6G -jar forge-1.12.2-14.23.5.2859.jar
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.<init>(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

C:\Users\kp\OneDrive\Desktop\Server (moded)>PAUSE
Press any key to continue . . .