NotBobthebuilder

I was going through the codakid mod creation manual and trying to learn how this stuff works, but when i ran the configuration setting they recommended, this problem appeared. the few solutions I found on the internet made no sense to me whatsoever. Can someone explain what exactly went wrong when i tried to run minecraft.(This happened when i ran the client, to make sure i hadn't screwed up somewhere, which it seems i did). Thank you. [2020-10-16 13:59:27] [INFO ] Natives: C:\Users\ultim\Desktop\Project minecraft\build\natives WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by net.minecraftforge.legacydev.MainClient (file:/C:/Users/ultim/.gradle/caches/modules-2/files-2.1/net.minecraftforge/legacydev/0.2.3.1/f2cd4a8c9f09faf1c1e4a9a4c65df36e634f95db/legacydev-0.2.3.1-fatjar.jar) to method java.lang.ClassLoader.initializePath(java.lang.String) WARNING: Please consider reporting this to the maintainers of net.minecraftforge.legacydev.MainClient WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release [2020-10-16 13:59:27] [INFO ] Main Class: net.minecraft.launchwrapper.Launch [2020-10-16 13:59:27] [INFO ] Srg2Mcp: C:\Users\ultim\Desktop\Project minecraft\build\createSrgToMcp\output.srg [2020-10-16 13:59:27] [INFO ] Extra: [] [2020-10-16 13:59:27] [INFO ] Running with arguments: [--version, 1.12, --assetIndex, 1.12, --assetsDir, C:\Users\ultim\.gradle\caches\forge_gradle\assets, --accessToken, {REDACTED}, --userProperties, [], --tweakClass, net.minecraftforge.fml.common.launcher.FMLTweaker] Exception in thread "main" java.lang.reflect.InvocationTargetException at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:564) at net.minecraftforge.legacydev.Main.start(Main.java:86) at net.minecraftforge.legacydev.MainClient.main(MainClient.java:29) 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) ... 6 more