Hello,

I tried modifying a vanilla loot table following the instructions it Forge documentations. However the game fails to load the modified loot table.

 

Code:

@SubscribeEvent
	public static void onLoottableLoad(LootTableLoadEvent event)
	{
		if (event.getName().equals(EntityType.ILLUSIONER.getLootTable()))
		{
			LootTable table = event.getLootTableManager().getLootTableFromLocation(new ResourceLocation(WTImprovements.MOD_ID + ":injects/illusioner"));
			LootPool pool = table.getPool(WTImprovements.MOD_ID + ":totem_of_decoy");
			event.getTable().addPool(pool);
		}
	}

 

Loot to add

{
	"type": "minecraft:entity",
	"pools": [
		{
			"name": "wt_improvements:totem_of_decoy",
			"rolls": 1,
			"entries": [
				{
					"type": "minecraft:item",
					"name": "wt_improvements:totem_of_decoy",
					"functions": [
						{
							"function": "minecraft:set_count",
							"count": {
								"min": 2.0,
								"max": 3.0,
								"type": "minecraft:uniform"
							}
						}
					]
				}
			]
		}
	]
}

 

Error message

java.lang.NullPointerException: null
	at java.util.ArrayList.forEach(Unknown Source) ~[?:1.8.0_171] {}
	at net.minecraft.loot.LootTable.freeze(LootTable.java:185) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at net.minecraftforge.common.ForgeHooks.loadLootTable(ForgeHooks.java:825) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at net.minecraft.loot.LootTableManager.lambda$apply$0(LootTableManager.java:40) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at java.util.HashMap.forEach(Unknown Source) ~[?:1.8.0_171] {}
	at net.minecraft.loot.LootTableManager.apply(LootTableManager.java:38) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at net.minecraft.loot.LootTableManager.apply(LootTableManager.java:16) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at net.minecraft.client.resources.ReloadListener.lambda$reload$1(ReloadListener.java:14) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at java.util.concurrent.CompletableFuture.uniAccept(Unknown Source) ~[?:1.8.0_171] {}
	at java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source) ~[?:1.8.0_171] {}
	at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_171] {}
	at net.minecraft.resources.AsyncReloader.lambda$null$3(AsyncReloader.java:66) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.run(ThreadTaskExecutor.java:139) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.RecursiveEventLoop.run(RecursiveEventLoop.java:22) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.driveOne(ThreadTaskExecutor.java:109) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.driveUntil(ThreadTaskExecutor.java:122) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.Minecraft.func_238189_a_(Minecraft.java:1866) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.func_238195_a_(Minecraft.java:1719) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.func_238191_a_(Minecraft.java:1689) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screen.WorldSelectionList$Entry.func_214443_e(WorldSelectionList.java:364) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screen.WorldSelectionList$Entry.func_214438_a(WorldSelectionList.java:273) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screen.WorldSelectionList$Entry.func_231044_a_(WorldSelectionList.java:225) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.widget.list.AbstractList.func_231044_a_(AbstractList.java:292) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.INestedGuiEventHandler.func_231044_a_(INestedGuiEventHandler.java:31) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.MouseHelper.lambda$mouseButtonCallback$0(MouseHelper.java:92) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screen.Screen.func_231153_a_(Screen.java:425) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.MouseHelper.mouseButtonCallback(MouseHelper.java:90) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.MouseHelper.lambda$null$4(MouseHelper.java:185) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.execute(ThreadTaskExecutor.java:86) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.MouseHelper.lambda$registerCallbacks$5(MouseHelper.java:184) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36) ~[lwjgl-glfw-3.2.2.jar:build 10] {}
	at org.lwjgl.system.JNI.invokeV(Native Method) ~[lwjgl-3.2.2.jar:build 10] {}
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3101) ~[lwjgl-glfw-3.2.2.jar:build 10] {}
	at com.mojang.blaze3d.systems.RenderSystem.flipFrame(RenderSystem.java:93) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.MainWindow.flipFrame(MainWindow.java:304) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1010) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.run(Minecraft.java:589) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(Main.java:184) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_171] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_171] {}
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_171] {}
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_171] {}
	at net.minecraftforge.userdev.FMLUserdevClientLaunchProvider.lambda$launchService$0(FMLUserdevClientLaunchProvider.java:52) ~[forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-7.0.1.jar:?] {}
	at net.minecraftforge.userdev.LaunchTesting.main(LaunchTesting.java:105) [forge-1.16.3-34.1.0_mapped_snapshot_20200514-1.16-recomp.jar:?] {}

 

The JSON itself seems to be fine. Does anyone know what's wrong with the loot table?

Thanks for any response.

This is more appropriate to global loot modifiers. You are modifying the table by appending an entry to it.