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[1.12] java.lang.reflect.Field cannot be cast to java.lang.Byte

josephcsible
in Modder Support

Featured Replies

Posted

While testing one of my mods alongside some others, I got this crash that I can't figure out:

Spoiler

---- Minecraft Crash Report ----

// But it works on my machine.

 

Time: 7/18/17 11:45 PM

Description: Ticking entity

 

java.lang.ClassCastException: java.lang.reflect.Field cannot be cast to java.lang.Byte

at net.minecraft.entity.EntityLivingBase.func_184587_cr(EntityLivingBase.java:2641)

at net.minecraft.entity.EntityLivingBase.func_184608_ct(EntityLivingBase.java:2651)

at net.minecraft.entity.EntityLivingBase.func_70071_h_(EntityLivingBase.java:2082)

at net.minecraft.entity.EntityLiving.func_70071_h_(EntityLiving.java:295)

at net.minecraft.entity.monster.EntityMob.func_70071_h_(SourceFile:46)

at net.minecraft.entity.monster.EntityCreeper.func_70071_h_(SourceFile:161)

at net.minecraft.world.World.func_72866_a(World.java:1976)

at net.minecraft.world.WorldServer.func_72866_a(WorldServer.java:833)

at net.minecraft.world.World.func_72870_g(World.java:1939)

at net.minecraft.world.World.func_72939_s(World.java:1753)

at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:614)

at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:761)

at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:665)

at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:185)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:523)

at java.lang.Thread.run(Thread.java:748)

 

 

A detailed walkthrough of the error, its code path and all known details is as follows:

---------------------------------------------------------------------------------------

 

-- Head --

Thread: Client thread

Stacktrace:

at net.minecraft.entity.EntityLivingBase.func_184587_cr(EntityLivingBase.java:2641)

at net.minecraft.entity.EntityLivingBase.func_184608_ct(EntityLivingBase.java:2651)

at net.minecraft.entity.EntityLivingBase.func_70071_h_(EntityLivingBase.java:2082)

at net.minecraft.entity.EntityLiving.func_70071_h_(EntityLiving.java:295)

at net.minecraft.entity.monster.EntityMob.func_70071_h_(SourceFile:46)

at net.minecraft.entity.monster.EntityCreeper.func_70071_h_(SourceFile:161)

at net.minecraft.world.World.func_72866_a(World.java:1976)

at net.minecraft.world.WorldServer.func_72866_a(WorldServer.java:833)

at net.minecraft.world.World.func_72870_g(World.java:1939)

 

-- Entity being ticked --

Details:

Entity Type: minecraft:creeper (net.minecraft.entity.monster.EntityCreeper)

Entity ID: 10719

Entity Name: Creeper

Entity's Exact location: -122.50, 44.00, 317.50

Entity's Block location: World: (-123,44,317), Chunk: (at 5,2,13 in -8,19; contains blocks -128,0,304 to -113,255,319), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)

Entity's Momentum: 0.00, -0.08, 0.00

Entity's Passengers: []

Entity's Vehicle: ~~ERROR~~ NullPointerException: null

Stacktrace:

at net.minecraft.world.World.func_72939_s(World.java:1753)

at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:614)

 

-- Affected level --

Details:

Level name: New World

All players: 1 total; [EntityPlayerMP['<PROFILE NAME>'/386, l='New World', x=-111.07, y=95.53, z=268.25]]

Chunk stats: ServerChunkCache: 630 Drop: 0

Level seed: 8382629383432640614

Level generator: ID 00 - default, ver 1. Features enabled: true

Level generator options:

Level spawn location: World: (-100,64,256), Chunk: (at 12,4,0 in -7,16; contains blocks -112,0,256 to -97,255,271), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)

Level time: 12128 game time, 6064 day time

Level dimension: 0

Level storage version: 0x04ABD - Anvil

Level weather: Rain time: 23809 (now: false), thunder time: 71243 (now: false)

Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true

Stacktrace:

at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:761)

at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:665)

at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:185)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:523)

at java.lang.Thread.run(Thread.java:748)

 

-- System Details --

Details:

Minecraft Version: 1.12

Operating System: Linux (amd64) version 4.12.0-041200-generic

Java Version: 1.8.0_131, Oracle Corporation

Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation

Memory: 2316900848 bytes (2209 MB) / 4064280576 bytes (3876 MB) up to 7635730432 bytes (7282 MB)

JVM Flags: 2 total; -Xms2048m -Xmx8192m

IntCache: cache: 0, tcache: 8, allocated: 20, tallocated: 86

FML: MCP 9.40 Powered by Forge 14.21.1.2413 8 mods loaded, 8 mods active

States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored

UCHIJAAAA minecraft{1.12} [Minecraft] (minecraft.jar)

UCHIJAAAA mcp{9.19} [Minecraft Coder Pack] (minecraft.jar)

UCHIJAAAA FML{8.0.99.99} [Forge Mod Loader] (forge-1.12-14.21.1.2413-universal.jar)

UCHIJAAAA forge{14.21.1.2413} [Minecraft Forge] (forge-1.12-14.21.1.2413-universal.jar)

UCHIJAAAA crafttweaker{4.0.1} [CraftTweaker2] (CraftTweaker2-1.12-4.0.1.jar)

UCHIJAAAA ctgui{1.0.0} [CT-GUI] (CraftTweaker2-1.12-4.0.1.jar)

UCHIJAAAA degradeexplodedblocks{1.0.0} [DegradeExplodedBlocks] (degradeexplodedblocks-1.11.2-1.0.0.jar)

UCHIJAAAA infinitefluids{1.1.1} [InfiniteFluids] (infinitefluids-1.11-1.1.1.jar)

Loaded coremods (and transformers):

GL info: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.

Profiler Position: N/A (disabled)

Player Count: 1 / 8; [EntityPlayerMP['<PROFILE NAME>'/386, l='New World', x=-111.07, y=95.53, z=268.25]]

Type: Integrated Server (map_client.txt)

Is Modded: Definitely; Client brand changed to 'fml,forge'

Important part:

java.lang.ClassCastException: java.lang.reflect.Field cannot be cast to java.lang.Byte

at net.minecraft.entity.EntityLivingBase.func_184587_cr(EntityLivingBase.java:2641)

 

Here's what I figured out myself:

First, here's net.minecraft.entity.EntityLivingBase.func_184587_cr(EntityLivingBase.java:2641): 

public boolean isHandActive()
{
	return (((Byte)this.dataManager.get(HAND_STATES)).byteValue() & 1) > 0;
}

HAND_STATES is declared as a DataParameter<Byte>, so all through this next part, T is Byte. Next, here's this.dataManager.get: 

public <T> T get(DataParameter<T> key)
{
	return (T)this.getEntry(key).getValue();
}

And here's getValue: 

public T getValue()
{
	return this.value;
}

And finally, here's value: 

private T value;

I don't get how a Field could have gotten as far as it did. "value" is declared as type T, as are the return values of getValue() and get(). Even get() itself has an explicit cast to T. Where did the Field come from here, and why didn't it crash anywhere prior to isHandActive where it must have been shoehorned into an inappropriate variable?

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