Null Error

package com.owenkelly05.tessmod.init;

import java.util.function.Supplier;

import com.owenkelly05.tessmod.TessMod;

import net.minecraft.item.IItemTier;
import net.minecraft.item.Item;
import net.minecraft.item.ItemGroup;
import net.minecraft.item.SwordItem;
import net.minecraft.item.crafting.Ingredient;
import net.minecraft.util.LazyValue;
import net.minecraftforge.event.RegistryEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.Mod.EventBusSubscriber.Bus;
import net.minecraftforge.registries.ObjectHolder;

@Mod.EventBusSubscriber(modid = TessMod.MOD_ID, bus = Bus.MOD)
@ObjectHolder(TessMod.MOD_ID)
public class ItemInit
{
//Items
	public static final Item test_item = null;

//Tools
	public static final Item tess_sword = null;

	@SubscribeEvent
	public static void registerItems(final RegistryEvent.Register<Item> event)
	{
		event.getRegistry().register(new Item(new Item.Properties().group(ItemGroup.MISC)).setRegistryName("test_item"));
//Tools
		event.getRegistry().register(new SwordItem(ModItemTier.EXAMPLE, 12, 3.0F, new Item.Properties().group(ItemGroup.COMBAT)));

	}

	public enum ModItemTier implements IItemTier
	{

EXAMPLE(4, 1500, 15.0F, 12.0F, 200, () -> {
	return Ingredient.fromItems(ItemInit.test_item);
	});

		private final int harvestLevel;
		private final int maxUses;
		private final float efficiency;
		private final float attackDamage;
		private final int enchantability;
		private final LazyValue<Ingredient> repairMaterial;


		private ModItemTier(int harvestLevel, int maxUses, float efficiency, float attackDamage, int enchantability, Supplier<Ingredient> repairMaterial)
		{
			this.harvestLevel = harvestLevel;
			this.maxUses = maxUses;
			this.efficiency = efficiency;
			this.attackDamage = attackDamage;
			this.enchantability = enchantability;
			this.repairMaterial = new LazyValue<>(repairMaterial);

		}


		@Override
		public int getMaxUses()
		{
			return this.maxUses;
		}


		@Override
		public float getEfficiency()
		{
			return this.efficiency;
		}


		@Override
		public float getAttackDamage()
		{
			return this.attackDamage;
		}


		@Override
		public int getHarvestLevel()
		{
			return this.harvestLevel;
		}


		@Override
		public int getEnchantability()
		{
			return this.enchantability;
		}


		@Override
		public Ingredient getRepairMaterial()
		{
			return this.repairMaterial.getValue();
		}
	}
}