ConcurrentModificationException in World.loadedEntityList

[Kinniken]

Hi guys,

 

I've had some users report crashes when using Millénaire with Forge with error logs like this:

 

---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 9/3/12 11:48 PM
Description: Exception in server tick loop

java.util.ConcurrentModificationException
    at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
    at java.util.AbstractList$Itr.next(Unknown Source)
    at java.util.AbstractCollection.removeAll(Unknown Source)
    at up.h(World.java:1820)
    at gr.h(WorldServer.java:437)
    at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:616)
    at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:547)
    at axv.p(IntegratedServer.java:102)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:453)
    at ep.run(SourceFile:539)

Relevant Details:
- Minecraft Version: 1.3.2
- Operating System: Windows 7 (amd64) version 6.1
- Java Version: 1.6.0_30, Sun Microsystems Inc.
- Java VM Version: Java HotSpot™ 64-Bit Server VM (mixed mode), Sun Microsystems Inc.
- Memory: 110421280 bytes (105 MB) / 527892480 bytes (503 MB) up to 954466304 bytes (910 MB)
- JVM Flags: 2 total; -Xms512m -Xmx1024m
- Is Modded: Definitely; 'forge,fml'
- Profiler Position: N/A (disabled)
- Player Count: 1 / 8; [gu['clownfish'/87, l='Clownfish Daddy', x=-275.28, y=68.25, z=382.80]]
- World Clownfish Daddy Entities: 0 total; []
- World Clownfish Daddy Players: 0 total; []
- World Clownfish Daddy Chunk Stats: ServerChunkCache: 0 Drop: 0
- Type: Integrated Server

 

This appears to happen when a loaded entity is removed from World.loadedEntityList. It's not clear from the reports whether this is caused by Millénaire or by Forge itself, though based on the trace it doesn't involve my code directly. Anybody has any idea as to the cause of this? I've tried reproducing it without success.

 

Thanks

 

K.

[rivvest]

Hi Kinniken!  Me again.. don't know why I'm obsessed

 

This thread http://www.minecraftforge.net/forum/index.php?topic=1504.0 got me thinking maybe there was some correlation between this and the tapestries/statues/carvings acting up and/or the disappearing raiding villagers.

 

I haven't been able to reliably replicate the crash, but I did get one that was almost the same but a little different in case that's any help.

 

2012-09-07 23:56:41 [iNFO] [sTDERR] java.util.ConcurrentModificationException

2012-09-07 23:56:41 [iNFO] [sTDERR] at java.util.HashMap$HashIterator.nextEntry(Unknown Source)

2012-09-07 23:56:41 [iNFO] [sTDERR] at java.util.HashMap$KeyIterator.next(Unknown Source)

2012-09-07 23:56:41 [iNFO] [sTDERR] at gm.a(EntityTracker.java:190)

2012-09-07 23:56:41 [iNFO] [sTDERR] at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:618)

[LexManos]

Typically this is caused by you adding a entity to the world in the wrong thread.

Check your tick events or anywhere where you spawn an entity in the world, or remove it.

You're probably on the client thread, dealing with the server world.