I am new to modding and I'm sure this is a simple fix but I cannot for the life of me figure out why this error is thrown. 

I am running forge-1.17.1-37.0.90 and all other aspects seem to be working fine

I am following this tutorial https://thebookofmodding.ml/adding-custom-items/

here is my code (sorry its messy rn) [registryhandler class]

https://imgur.com/a/EGC2jyj

package com.example.examplemod;

import net.minecraft.item.ItemGroup;
import net.minecraft.world.item.Item;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
import net.minecraftforge.fmllegacy.RegistryObject;
import net.minecraftforge.registries.DeferredRegister;
import net.minecraftforge.registries.ForgeRegistries;
/*
public class RegistryHandler {
    // create DeferredRegister object
    public static final DeferredRegister<Item> ITEMS = DeferredRegister.create(ForgeRegistries.ITEMS, ExampleMod.MODID);

    public static void init() {
        // attach DeferredRegister to the event bus
        ITEMS.register(FMLJavaModLoadingContext.get().getModEventBus());
    }

    // register item
   public static final RegistryObject<Item> COPPER = ITEMS.register("copper", () ->
        //    new Item(new Item.Properties().group(ItemGroup.MATERIALS))
       //     );
                new Item(
                    new Item.Properties().group(ItemGroup.MATERIALS)
           )
    );

 */
    public class RegistryHandler {
        public static final DeferredRegister<Item> ITEMS = DeferredRegister.create(ForgeRegistries.ITEMS, ExampleMod.MODID);

        public static void init() {
            // attach DeferredRegister to the event bus
            ITEMS.register(FMLJavaModLoadingContext.get().getModEventBus());
        }

        public static final RegistryObject<Item> TITAN = ITEMS.register("titan",
                ()-> new Item(new Item.Properties().group(ItemGroup.REDSTONE)));
    }

 

Edited October 18, 20214 yr by parkat

ItemGroup belongs to the net.minecraft.item package, not "items"

1 hour ago, izofar said:

ItemGroup belongs to the net.minecraft.item package, not "items"

that doesn't work either 

Forge use now Mojang class names and their package names, you can use the Forge bot on discord to convert from mcp to moj mappings 

But I would recommend you to use this scrip it will update your hole project automatically 

Edited October 19, 20214 yr by Luis_ST

12 hours ago, Luis_ST said:

Forge use now Mojang class names and their package names, you can use the Forge bot on discord to convert from mcp to moj mappings 

But I would recommend you to use this scrip it will update your hole project automatically 

thank you! this works!!