[1.12.2] [SOLVED] Late update of ObjectHolder causes NullPointerException

[AndreiiiH]

Hello,

 

I am currently experiencing an issue, where by following the latest docs on how to register and store your blocks and tile entities, you end up with an error:

 

Spoiler

[02:00:05] [Client thread/ERROR] [FML]: Exception caught during firing event net.minecraftforge.event.RegistryEvent$Register@5ffac740:
java.lang.NullPointerException: null
	at andreihava.electricalengineer.proxy.CommonProxy.registerBlocks(CommonProxy.java:41) ~[CommonProxy.class:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_4_CommonProxy_registerBlocks_Register.invoke(.dynamic) ~[?:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) ~[ASMEventHandler.class:?]
	at net.minecraftforge.fml.common.eventhandler.EventBus$1.invoke(EventBus.java:144) ~[EventBus$1.class:?]
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) [EventBus.class:?]
	at net.minecraftforge.registries.GameData.fireRegistryEvents(GameData.java:804) [GameData.class:?]
	at net.minecraftforge.fml.common.Loader.preinitializeMods(Loader.java:628) [Loader.class:?]
	at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:252) [FMLClientHandler.class:?]
	at net.minecraft.client.Minecraft.init(Minecraft.java:514) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.run(Minecraft.java:422) [Minecraft.class:?]
	at net.minecraft.client.main.Main.main(Main.java:118) [Main.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_191]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_191]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_191]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_191]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_191]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_191]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_191]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_191]
	at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97) [start/:?]
	at GradleStart.main(GradleStart.java:25) [start/:?]

Gist: https://gist.github.com/AndreiiiH/1df4171070554ab83eb86c8a03464abe

 

This error is caused by the ObjectHoldermembers of the ModBlocks.java class not yet being initialized, which is expected, as per Forge docs (link to docs) :

Quote

The order in which RegistryEvent.Register events fire is alphabetically, with the exception that Block will always fire first, and Item will always fire second, right after Block. After the Register<Block> event has fired, all ObjectHolder annotations are refreshed, and after Register<Item> has fired they are refreshed again. They are refreshed for a third time after all of the other Register events have fired.

 

But then, the TileEntity part of the docs recommends registration of all Blocks (including TileEntities) to happen in the RegistrationEvents (link to docs) :

Quote

At this point you can either choose to do it during the FMLPreInitializationEvent or during the RegistryEvent.Register<Block> event, as TileEntities don’t have their own Registry Event yet.

 

Because of the recent deprecation of GameRegistry.registerTileEntity(Class, String); in favor of GameRegistry.registerTileEntity(Class, ResourceLocation);, this now causes an issue. Perhaps I am attempting to retrieve the ResourceLocation instance incorrectly?

 

My ModBlocks class:

Spoiler

@GameRegistry.ObjectHolder("electricalengineer")
public class ModBlocks {

    @GameRegistry.ObjectHolder("electricsparkblock")
    public static BlockElectricSpark ELECTRIC_SPARK;

    @GameRegistry.ObjectHolder("capacitor")
    public static BlockCapacitor CAPACITOR;
}

Gist: https://gist.github.com/AndreiiiH/680ee2345ab4866fc6f6c94820e9815c

 

My CommonProxy class:

Spoiler

package andreihava.electricalengineer.proxy;

import [...]

@Mod.EventBusSubscriber
public class CommonProxy {

    [... Init Methods ...]

    @SubscribeEvent
    public static void registerBlocks(RegistryEvent.Register<Block> event) {
        // BLOCKS
        event.getRegistry().register(new BlockElectricSpark());
        event.getRegistry().register(new BlockCapacitor());

        // TILE ENTITIES
        GameRegistry.registerTileEntity(ModBlocks.CAPACITOR.getTileEntityClass(), ModBlocks.CAPACITOR.getRegistryName());
    }

    @SubscribeEvent
    public static void registerItems(RegistryEvent.Register<Item> event) {
        // BLOCK ITEMS
        event.getRegistry().register(new ItemBlock(ModBlocks.ELECTRIC_SPARK).setRegistryName(ModBlocks.ELECTRIC_SPARK.getRegistryName()));
        event.getRegistry().register(new ItemBlock(ModBlocks.CAPACITOR).setRegistryName(ModBlocks.CAPACITOR.getRegistryName()));

        // NORMAL ITEMS
        event.getRegistry().register(new ItemElectricSpark());
    }
}

Gist: https://gist.github.com/AndreiiiH/84b77e3aa51e622022302ce8f8feb3bc

 

For now, I can botch my way out of the error by moving the TileEntity registration to registerItems, as such:

Spoiler

@SubscribeEvent
public static void registerItems(RegistryEvent.Register<Item> event) {
    // TILE ENTITIES
    // TODO: Temp botch due to ObjectHolder late update causing NullPointerException
    GameRegistry.registerTileEntity(ModBlocks.CAPACITOR.getTileEntityClass(), ModBlocks.CAPACITOR.getRegistryName());

    // BLOCK ITEMS
    event.getRegistry().register(new ItemBlock(ModBlocks.ELECTRIC_SPARK).setRegistryName(ModBlocks.ELECTRIC_SPARK.getRegistryName()));
    event.getRegistry().register(new ItemBlock(ModBlocks.CAPACITOR).setRegistryName(ModBlocks.CAPACITOR.getRegistryName()));

    // NORMAL ITEMS
    event.getRegistry().register(new ItemElectricSpark());
}

Gist: https://gist.github.com/AndreiiiH/715a4ca75ee09ae6e05800bcc5224a10

 

This is not ideal as TileEntity registration should not be happening there.

 

Perhaps you can shed some light on this issue.

 

Thank you!

Edited January 13, 2019 by AndreiiiH
Marked as solved

[AndreiiiH]

Thank you, @diesieben07!

 

Changing my method to

Spoiler

@SubscribeEvent
public static void registerBlocks(RegistryEvent.Register<Block> event) {
    // BLOCKS
    event.getRegistry().register(new BlockElectricSpark());
    event.getRegistry().register(new BlockCapacitor());

    // TILE ENTITIES
    GameRegistry.registerTileEntity(TileEntityCapacitor.class, new ResourceLocation(Constants.MOD_ID, "tile_capacitor"));
}

 

has fixed my issue.

 

Also, thank you for pointing out my code style issue! I'll make sure to change this ASAP. It's my first mod I'm working on, so I'm learning as I go, thus the code is a mess.

Edited January 13, 2019 by AndreiiiH