Danebi

This is a Java error. Learn Java before modding.

A packet?

Now delete this.

Java 15 removed the Nashorn engine that is used by Forge. Downgrade to a supported version.

Try to run JarFix.

Then probably all... Did you read this?

Problematic Code #8 and Code-Style #4 Don't register items and blocks dynamically. To get the instance of a registry entry (like Item and Block) use RegistryObject#get.

If you're not a modder why do you want to modify the license?

Sorry, but i can't make any sense of what you sent... maybe there was some problem when copying the code? If what you posted is really your code learn Java.

Have you tried searching online?

You have to shadow the dependency in the jar.

Installations

A git repository with all your code.

Maybe it hasn't been mapped?

You can override it. You are creating the ItemEntity but aren't spawning it.

Post a repo.

Can you stop capitalizing every word?

Have you tried learning Java first?

ObfuscationReflectionHelper#getPrivateValue

So... you used a Java class without knowing java? It's obvious it didn't work. Also, didn't you continue to say "command" instead of method in you previous thread? If you knew C++ you would have known what a method or a function are. Access transformers but using reflection would be better.

Yes, I actually wanted to write other things but I got distracted and sent as it was. Then i completely forgot about it...😅 I doubt it... if you knew C ++ you wouldn't have so much problems learning Java.

Can someone explain me why should a corrupted config file crash the computer?

Oh, you're the charged creeper guy? Forge modding isn't difficult. You're making it difficult. You have to learn java first.

No, you don't... make your own thread and post the debug.log.

Post your code and the debug.log.