I tried to add an custom Entity into Minecraft, but i get this error:

[16:48:36] [Server thread/FATAL] [minecraft/ThreadTaskExecutor]: Error executing task on Server
java.lang.NullPointerException: null
	at net.minecraft.network.datasync.EntityDataManager.set(EntityDataManager.java:122) ~[forge:?] {re:classloading}
	at net.minecraft.entity.LivingEntity.setHealth(LivingEntity.java:924) ~[forge:?] {re:classloading}
	at net.minecraft.entity.LivingEntity.<init>(LivingEntity.java:207) ~[forge:?] {re:classloading}
	at net.tomschmidt.drones.entity.DroneEntity.<init>(DroneEntity.java:23) ~[?:?] {re:classloading}
	at net.tomschmidt.drones.items.DroneSpawnItem.onItemUseFirst(DroneItem.java:35) ~[?:?] {re:classloading}
	at net.minecraft.item.ItemStack.lambda$onItemUseFirst$6(ItemStack.java:191) ~[forge:?] {re:classloading,xf:fml:forge:filled_map.4,xf:fml:forge:itemstack}
	at net.minecraft.item.ItemStack.onItemUse(ItemStack.java:202) ~[forge:?] {re:classloading,xf:fml:forge:filled_map.4,xf:fml:forge:itemstack}
	at net.minecraft.item.ItemStack.onItemUseFirst(ItemStack.java:191) ~[forge:?] {re:classloading,xf:fml:forge:filled_map.4,xf:fml:forge:itemstack}
	at net.minecraft.server.management.PlayerInteractionManager.useItemOn(PlayerInteractionManager.java:331) ~[forge:?] {re:classloading}
	at net.minecraft.network.play.ServerPlayNetHandler.handleUseItemOn(ServerPlayNetHandler.java:958) ~[forge:?] {re:classloading}
	at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.handle(CPlayerTryUseItemOnBlockPacket.java:36) ~[forge:?] {re:classloading}
	at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.handle(CPlayerTryUseItemOnBlockPacket.java:12) ~[forge:?] {re:classloading}
	at net.minecraft.network.PacketThreadUtil.lambda$ensureRunningOnSameThread$0(PacketThreadUtil.java:19) ~[forge:?] {re:classloading}
	at net.minecraft.util.concurrent.TickDelayedTask.run(TickDelayedTask.java:17) ~[forge:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.doRunTask(ThreadTaskExecutor.java:136) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.RecursiveEventLoop.doRunTask(RecursiveEventLoop.java:22) ~[forge:?] {re:classloading}
	at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:734) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:159) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.pollTask(ThreadTaskExecutor.java:109) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.server.MinecraftServer.pollTaskInternal(MinecraftServer.java:717) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:711) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.managedBlock(ThreadTaskExecutor.java:119) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.server.MinecraftServer.waitUntilNextTick(MinecraftServer.java:697) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:646) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:232) ~[forge:?] {re:classloading,pl:accesstransformer:B}
	at java.lang.Thread.run(Thread.java:750) [?:1.8.0_342] {}

(I try to spawn my Entity with an extra Item but the same happens with the summon command)

Other people in this forum had similiar errors, but they could fix it with 

    public static AttributeModifierMap.MutableAttribute setCustomAttributes() {
        return LivingEntity.createLivingAttributes()
                .add(Attributes.MAX_HEALTH, 20.0f);
    }

and

@Mod.EventBusSubscriber(modid = Drones.MOD_ID, bus = Mod.EventBusSubscriber.Bus.MOD)
public class ModEventBusEvents {

    @SubscribeEvent
    public static void addEntityAttributes(EntityAttributeCreationEvent event) {
        CombatDrones.LOGGER.info("ID22, EntityAttributeCreationEvent"); //is executed (shows in log)
        event.put(ModEntityTypes.DRONE.get(), DroneEntity.setCustomAttributes().build());
        CombatDrones.LOGGER.info("HasSupplier: " + GlobalEntityTypeAttributes.hasSupplier(ModEntityTypes.DRONE.get())); //returns true
    }
}

But i already did this and that confuses me.

Does anyone know the solution for my problem?

PS: excuse my typos, i am not an native english speaker.

Edited September 17, 20223 yr by tomschmidt

Provide the entirety of your custom entity class.

My whole entity class:

package net.tomschmidt.drones.entity;

import net.tomschmidt.drones.register.ModEntityTypes;
import net.minecraft.entity.Entity;
import net.minecraft.entity.EntityType;
import net.minecraft.entity.LivingEntity;
import net.minecraft.entity.ai.attributes.Attribute;
import net.minecraft.entity.ai.attributes.AttributeModifierMap;
import net.minecraft.entity.ai.attributes.Attributes;
import net.minecraft.inventory.EquipmentSlotType;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.CompoundNBT;
import net.minecraft.network.IPacket;
import net.minecraft.util.HandSide;
import net.minecraft.util.math.MathHelper;
import net.minecraft.util.math.vector.Vector3d;
import net.minecraft.world.World;


public class DroneEntity extends LivingEntity {
    public DroneEntity(EntityType<? extends DroneEntity> p_i48580_1_, World p_i48580_2_) {
        super(p_i48580_1_, p_i48580_2_);
    }

    public void setStartPos(double x, double y, double z) {
        this.setPos(x, y, z);
        this.setDeltaMovement(Vector3d.ZERO);
        this.xo = x;
        this.yo = y;
        this.zo = z;
    }

    @Override
    protected void defineSynchedData() {

    }

    @Override
    public Iterable<ItemStack> getArmorSlots() {
        return null;
    }

    @Override
    public ItemStack getItemBySlot(EquipmentSlotType p_184582_1_) {
        return null;
    }

    @Override
    public void setItemSlot(EquipmentSlotType p_184201_1_, ItemStack p_184201_2_) {

    }

    @Override
    public HandSide getMainArm() {
        return HandSide.RIGHT;
    }

    @Override
    public IPacket<?> getAddEntityPacket() {
        return null;
    }

    public static AttributeModifierMap.MutableAttribute setCustomAttributes() {
        return LivingEntity.createLivingAttributes()
                .add(Attributes.MAX_HEALTH, 20.0f);
    }

}

 

You have a lot of methods that return null and don't call the super of a method, which causes plenty of errors. However, the code provided is for 1.16.5, which is not supported on this forum. If you would like to provide the updated 1.18.2 code, I will give a proper answer. Otherwise, I will lock this thread since it is no longer supported.

Additionally, the answer I'll provide will not work in 1.16.5 due to the changes past 1.17.

This mod will be an addon to an existing mod, which only exists in 1.16.5 so updating is completely useless and I need a solution for this version.

If I update it to get an answer I have to backport it which not sounds like a solution.

 

Then apologies, but then we cannot help you on this forum:

The version you are using is no longer supported on this forum.

Please update to a modern version of Minecraft to receive support.

Currently supported versions are 1.19.2 (Latest) and 1.18.2 (LTS).