ConcurrentModificationException while spawning structures in a chunk.

Posted September 30, 201212 yr

Getting the following error when working with Structures...

The only thing I found when searching this site and google are when people are spawning entities in the client thread, nothing about Structures spawning in a chunk.

Any ideas? Thanks.

2012-09-30 14:40:35 [iNFO] [sTDERR] java.util.ConcurrentModificationException
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at java.util.HashMap$ValueIterator.next(Unknown Source)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.MapGenStructure.generateStructuresInChunk(MapGenStructure.java:47)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at micdoodle8.mods.galacticraft.GCChunkProvider.populate(GCChunkProvider.java:451)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ChunkProviderServer.populate(ChunkProviderServer.java:218)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.Chunk.populateChunk(Chunk.java:1180)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ChunkProviderServer.loadChunk(ChunkProviderServer.java:118)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ChunkProviderServer.provideChunk(ChunkProviderServer.java:131)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.World.isBlockSolidOnSide(World.java:4095)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at micdoodle8.mods.galacticraft.GCBlockUnlitTorch.onBlockAdded(GCBlockUnlitTorch.java:151)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.Chunk.setBlockIDWithMetadata(Chunk.java:691)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.World.setBlockAndMetadataWithUpdate(World.java:405)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.World.setBlockAndMetadata(World.java:383)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.StructureComponent.placeBlockAtCurrentPosition(StructureComponent.java:536)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at micdoodle8.mods.galacticraft.GCComponentCreeperPitCorridor.addComponentParts(GCComponentCreeperPitCorridor.java:116)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.StructureStart.generateStructure(StructureStart.java:36)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.MapGenStructure.generateStructuresInChunk(MapGenStructure.java:51)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at micdoodle8.mods.galacticraft.GCChunkProvider.populate(GCChunkProvider.java:451)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ChunkProviderServer.populate(ChunkProviderServer.java:218)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.Chunk.populateChunk(Chunk.java:1180)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ChunkProviderServer.loadChunk(ChunkProviderServer.java:118)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ChunkProviderServer.provideChunk(ChunkProviderServer.java:131)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.World.getChunkFromChunkCoords(World.java:375)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.WorldServer.getAllTileEntityInBox(WorldServer.java:568)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.EntityPlayerMP.localOnUpdate(EntityPlayerMP.java:1190)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ServerPlayerBase.onUpdate(ServerPlayerBase.java:764)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at micdoodle8.mods.galacticraft.GCPlayerBaseServer.onUpdate(GCPlayerBaseServer.java:175)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ServerPlayerAPI.onUpdate(ServerPlayerAPI.java:3554)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ServerPlayerAPI.onUpdate(ServerPlayerAPI.java:3532)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.EntityPlayerMP.onUpdate(EntityPlayerMP.java:1145)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.World.updateEntityWithOptionalForce(World.java:2056)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.WorldServer.updateEntityWithOptionalForce(WorldServer.java:535)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.World.updateEntity(World.java:2021)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.World.updateEntities(World.java:1902)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.WorldServer.updateEntities(WorldServer.java:434)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:631)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:562)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.IntegratedServer.tick(IntegratedServer.java:107)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:468)
2012-09-30 14:40:35 [iNFO] [sTDERR] 	at net.minecraft.src.ThreadServerApplication.run(ThreadServerApplication.java:18)

Quote

October 1, 201212 yr

You need to be careful when you create recursive loops:

2012-09-30 14:40:35 [iNFO] [sTDERR] at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
2012-09-30 14:40:35 [iNFO] [sTDERR] at java.util.HashMap$ValueIterator.next(Unknown Source)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.MapGenStructure.generateStructuresInChunk(MapGenStructure.java:47)

2012-09-30 14:40:35 [iNFO] [sTDERR] at micdoodle8.mods.galacticraft.GCChunkProvider.populate(GCChunkProvider.java:451)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.ChunkProviderServer.populate(ChunkProviderServer.java:218)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.Chunk.populateChunk(Chunk.java:1180)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.ChunkProviderServer.loadChunk(ChunkProviderServer.java:118)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.ChunkProviderServer.provideChunk(ChunkProviderServer.java:131)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.World.isBlockSolidOnSide(World.java:4095)

2012-09-30 14:40:35 [iNFO] [sTDERR] at micdoodle8.mods.galacticraft.GCBlockUnlitTorch.onBlockAdded(GCBlockUnlitTorch.java:151)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.Chunk.setBlockIDWithMetadata(Chunk.java:691)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.World.setBlockAndMetadataWithUpdate(World.java:405)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.World.setBlockAndMetadata(World.java:383)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.StructureComponent.placeBlockAtCurrentPosition(StructureComponent.java:536)

2012-09-30 14:40:35 [iNFO] [sTDERR] at micdoodle8.mods.galacticraft.GCComponentCreeperPitCorridor.addComponentParts(GCComponentCreeperPitCorridor.java:116)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.StructureStart.generateStructure(StructureStart.java:36)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.MapGenStructure.generateStructuresInChunk(MapGenStructure.java:51)

2012-09-30 14:40:35 [iNFO] [sTDERR] at micdoodle8.mods.galacticraft.GCChunkProvider.populate(GCChunkProvider.java:451)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.ChunkProviderServer.populate(ChunkProviderServer.java:218)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.Chunk.populateChunk(Chunk.java:1180)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.ChunkProviderServer.loadChunk(ChunkProviderServer.java:118)

2012-09-30 14:40:35 [iNFO] [sTDERR] at net.minecraft.src.ChunkProviderServer.provideChunk(ChunkProviderServer.java:131)

See the recursion?

I do Forge for free, however the servers to run it arn't free, so anything is appreciated.
Consider supporting the team on Patreon

Quote

October 1, 201212 yr

Author

Okay I see it now in that one, but getting a different stack trace now...

java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
at java.util.HashMap$ValueIterator.next(Unknown Source)
at net.minecraft.src.MapGenStructure.generateStructuresInChunk(MapGenStructure.java:47)
at micdoodle8.mods.galacticraft.GCChunkProvider.populate(GCChunkProvider.java:451)
at net.minecraft.src.ChunkProviderServer.populate(ChunkProviderServer.java:218)
at net.minecraft.src.Chunk.populateChunk(Chunk.java:1185)
at net.minecraft.src.ChunkProviderServer.loadChunk(ChunkProviderServer.java:118)
at net.minecraft.src.PlayerInstance.<init>(PlayerInstance.java:26)
at net.minecraft.src.PlayerManager.getOrCreateChunkWatcher(PlayerManager.java:88)
at net.minecraft.src.PlayerManager.updateMountedMovingPlayer(PlayerManager.java:244)
at net.minecraft.src.ServerConfigurationManager.serverUpdateMountedMovingPlayer(ServerConfigurationManager.java:197)
at net.minecraft.src.NetServerHandler.handleFlying(NetServerHandler.java:341)
at net.minecraft.src.Packet10Flying.processPacket(Packet10Flying.java:51)
at net.minecraft.src.MemoryConnection.processReadPackets(MemoryConnection.java:78)
at net.minecraft.src.NetServerHandler.networkTick(NetServerHandler.java:76)
at net.minecraft.src.NetworkListenThread.networkTick(NetworkListenThread.java:55)
at net.minecraft.src.IntegratedServerListenThread.networkTick(IntegratedServerListenThread.java:111)
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:645)
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:562)
at net.minecraft.src.IntegratedServer.tick(IntegratedServer.java:107)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:468)
at net.minecraft.src.ThreadServerApplication.run(ThreadServerApplication.java:18)

Quote

October 1, 201212 yr

Still has issues with running that code, while its already running.

Its obvious what its trying to itterate over, make sure while its itterating it it doesnt add or remove to the array.

I do Forge for free, however the servers to run it arn't free, so anything is appreciated.
Consider supporting the team on Patreon

Quote

October 1, 201212 yr

Author

Ahh, it was a bad for loop yep... I did it exactly the same as the vanilla code, so I don't know why.

Anyway thanks Lex.

Quote

October 5, 201212 yr

Author

Still getting them, even though I'm following the way that the vanilla code does.

Error:

http://pastebin.com/tZB8G10u

Source:

https://github.com/micdoodle8/Galacticraft/blob/master/src/common/micdoodle8/mods/galacticraft/GCComponentCreeperPitRoom.java

Quote

October 5, 201212 yr

Note: I'm not a Java programmer, I just like puzzles.

buildComponent() calls makeCorridor() 4 times. Every call to makeCorridor() calls buildComponent(). Am I missing the way out of this loop? I suspect the list.add(var12) is causing the CME.. is something iterating over this list when the add() happens?

I'm fixing the stupid villagers. http://www.minecraftforum.net/topic/1588460-

Quote

October 5, 201212 yr

Author

Note: I'm not a Java programmer, I just like puzzles.

buildComponent() calls makeCorridor() 4 times. Every call to makeCorridor() calls buildComponent(). Am I missing the way out of this loop? I suspect the list.add(var12) is causing the CME.. is something iterating over this list when the add() happens?

Well makeCorridor() is calling buildComponent() in the corridor class, so it wouldn't create an infinite loop. The cme is in MapGenStructure, which is code I don't access and never edited.

Quote

October 10, 201212 yr

Author

Sorry for bumping, but I really need this fixed...

Quote

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ConcurrentModificationException while spawning structures in a chunk.

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