I tried to add a drop item to the Spider but I just couldn't overwrite anything. Help is appreciated and sorry if I'm just stupid.

The class:

 

package de.theyoungseth.randomutils.utilities;

import net.minecraft.entity.EntityType;
import net.minecraft.item.Items;
import net.minecraft.world.storage.loot.*;
import net.minecraft.world.storage.loot.conditions.KilledByPlayer;
import net.minecraft.world.storage.loot.functions.LootingEnchantBonus;
import net.minecraft.world.storage.loot.functions.SetCount;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;

import java.util.function.Consumer;

@Mod.EventBusSubscriber(modid = References.MODID)
public class EntityLootTables extends net.minecraft.data.loot.EntityLootTables {

    @Override
    @SubscribeEvent
    protected void addTables() {
        super.addTables();
        this.registerLootTable(EntityType.SPIDER, LootTable.builder().addLootPool(LootPool.builder().rolls(ConstantRange.of(1)).addEntry(ItemLootEntry.builder(ItemRegistryHandler.spider).acceptFunction(SetCount.builder(RandomValueRange.of(0.0F, 1.0F))).acceptFunction(LootingEnchantBonus.builder(RandomValueRange.of(0.0F, 1.0F))))).addLootPool(LootPool.builder().rolls(ConstantRange.of(1)).addEntry(ItemLootEntry.builder(Items.STRING).acceptFunction(SetCount.builder(RandomValueRange.of(0.0F, 2.0F))).acceptFunction(LootingEnchantBonus.builder(RandomValueRange.of(0.0F, 1.0F))))).addLootPool(LootPool.builder().rolls(ConstantRange.of(1)).addEntry(ItemLootEntry.builder(Items.SPIDER_EYE).acceptFunction(SetCount.builder(RandomValueRange.of(-1.0F, 1.0F))).acceptFunction(LootingEnchantBonus.builder(RandomValueRange.of(0.0F, 1.0F)))).acceptCondition(KilledByPlayer.builder())));
    }

    /*@SubscribeEvent
    public void addTables() {
        this.registerLootTable(EntityType.SPIDER, LootTable.builder().addLootPool(LootPool.builder().rolls(ConstantRange.of(1)).addEntry(ItemLootEntry.builder(ItemRegistryHandler.spider).acceptFunction(SetCount.builder(RandomValueRange.of(0.0F, 1.0F))).acceptFunction(LootingEnchantBonus.builder(RandomValueRange.of(0.0F, 1.0F))))).addLootPool(LootPool.builder().rolls(ConstantRange.of(1)).addEntry(ItemLootEntry.builder(Items.STRING).acceptFunction(SetCount.builder(RandomValueRange.of(0.0F, 2.0F))).acceptFunction(LootingEnchantBonus.builder(RandomValueRange.of(0.0F, 1.0F))))).addLootPool(LootPool.builder().rolls(ConstantRange.of(1)).addEntry(ItemLootEntry.builder(Items.SPIDER_EYE).acceptFunction(SetCount.builder(RandomValueRange.of(-1.0F, 1.0F))).acceptFunction(LootingEnchantBonus.builder(RandomValueRange.of(0.0F, 1.0F)))).acceptCondition(KilledByPlayer.builder())));
    }*/
}

 

Try making the method static. I EventBusSubscriber requires a static method.

Wait, I didn't read properly. I'm also new and have not fiddled with loot tables but why are subscribing to an event without a parameter.

https://mcforge.readthedocs.io/en/1.13.x/events/intro/

and for adding drops you need to use https://github.com/MinecraftForge/Documentation/pull/274