java.util.ConcurrentModificationException error

Randomly got this error. It crashed the server. Any idea what it is?

Code:

2011-11-03 16:14:02 [SEVERE] java.util.ConcurrentModificationException
2011-11-03 16:14:02 [SEVERE]     at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
2011-11-03 16:14:02 [SEVERE]     at java.util.AbstractList$Itr.next(AbstractList.java:343)
2011-11-03 16:14:02 [SEVERE]     at java.util.AbstractCollection.removeAll(AbstractCollection.java:336)
2011-11-03 16:14:02 [SEVERE]     at net.minecraft.server.World.tickEntities(World.java:1058)
2011-11-03 16:14:02 [SEVERE]     at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:467)
2011-11-03 16:14:02 [SEVERE]     at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
2011-11-03 16:14:02 [SEVERE]     at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)
2011-11-03 16:14:02 [SEVERE] Unexpected exception
java.util.ConcurrentModificationException
    at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
    at java.util.AbstractList$Itr.next(AbstractList.java:343)
    at java.util.AbstractCollection.removeAll(AbstractCollection.java:336)
    at net.minecraft.server.World.tickEntities(World.java:1058)
    at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:467)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)
2011-11-03 16:14:33 [INFO] Connection reset

 

i get this all the damn time its killing me

2011-11-06 15:06:59 [SEVERE] java.util.ConcurrentModificationException
2011-11-06 15:06:59 [SEVERE] at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
2011-11-06 15:06:59 [SEVERE] at java.util.AbstractList$Itr.next(Unknown Source)
2011-11-06 15:06:59 [SEVERE] at java.util.AbstractCollection.removeAll(Unknown Source)
2011-11-06 15:06:59 [SEVERE] at net.minecraft.server.World.tickEntities(World.java:1058)
2011-11-06 15:06:59 [SEVERE] at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:467)
2011-11-06 15:06:59 [SEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
2011-11-06 15:06:59 [SEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)
2011-11-06 15:06:59 [SEVERE] Unexpected exception
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 net.minecraft.server.World.tickEntities(World.java:1058)
at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:467)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)
2011-11-06 15:07:09 [INFO] Connection reset

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

freaking bump

 

how u fix

 

You don't. Seems like a Bukkit/Minecraft-internal thing. Someone is iterating over a collection (or a set) while someone else is altering it. That's how you get a ConcurrentModificationException.

 

By "someone", @Brain means "threads".
This could be, but I don't think it's Bukkit related.

Possibly one of your plugins is altering a Collection while iterating over it, like this:

Code:

for (String s : collection){
  collection.remove(s);
}

Also, please read this.

 

Yeah I get the same damn thing and Each time try anyone connects, it always read time out. And it also keep throwing Reached End of Stream messages PLEASE HELP!!!!

14:35:29 [SEVERE] java.util.ConcurrentModificationException
14:35:29 [SEVERE] at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
14:35:29 [SEVERE] at java.util.AbstractList$Itr.next(AbstractList.java:343)
14:35:29 [SEVERE] at java.util.AbstractCollection.removeAll(AbstractCollection.java:336)
14:35:29 [SEVERE] at net.minecraft.server.World.tickEntities(World.java:1109)
14:35:29 [SEVERE] at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:518)
14:35:29 [SEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
14:35:29 [SEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
14:35:29 [SEVERE] Unexpected exception
java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)
at java.util.AbstractCollection.removeAll(AbstractCollection.java:336)
at net.minecraft.server.World.tickEntities(World.java:1109)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:518)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
14:35:43 [INFO] Reached end of stream
14:36:08 [INFO] Reached end of stream
14:36:34 [INFO] Reached end of stream
14:36:59 [INFO] Reached end of stream
14:37:24 [INFO] Reached end of stream
14:37:49 [INFO] Reached end of stream
14:38:14 [INFO] Reached end of stream
14:38:39 [INFO] Reached end of stream
14:39:04 [INFO] Reached end of stream
14:39:29 [INFO] Reached end of stream
14:39:54 [INFO] Reached end of stream
14:40:19 [INFO] Reached end of stream
14:40:44 [INFO] Reached end of stream
14:41:10 [INFO] Reached end of stream
14:41:35 [INFO] Reached end of stream
14:42:25 [INFO] Reached end of stream
14:42:50 [INFO] Reached end of stream
14:43:15 [INFO] Reached end of stream
14:43:40 [INFO] Reached end of stream
14:44:05 [INFO] Reached end of stream
14:44:30 [INFO] Reached end of stream
14:44:55 [INFO] Reached end of stream
14:45:20 [INFO] Reached end of stream
14:45:45 [INFO] Reached end of stream
14:46:10 [INFO] Reached end of stream
14:46:35 [INFO] Reached end of stream
14:47:00 [INFO] Reached end of stream
14:47:25 [INFO] Reached end of stream
14:47:50 [INFO] Reached end of stream
14:48:16 [INFO] Reached end of stream
14:48:41 [INFO] Reached end of stream
14:49:06 [INFO] Reached end of stream
14:49:31 [INFO] Reached end of stream
14:49:56 [INFO] Reached end of stream
14:50:21 [INFO] Reached end of stream
14:50:46 [INFO] Reached end of stream
14:51:14 [INFO] Reached end of stream
14:51:39 [INFO] Reached end of stream
14:52:04 [INFO] Reached end of stream
14:52:29 [INFO] Reached end of stream
14:52:54 [INFO] Reached end of stream
14:53:19 [INFO] Reached end of stream
14:53:44 [INFO] Reached end of stream
14:54:09 [INFO] Reached end of stream
14:54:34 [INFO] Reached end of stream
14:54:59 [INFO] Reached end of stream
14:55:24 [INFO] Reached end of stream
14:55:49 [INFO] Reached end of stream
14:56:14 [INFO] Reached end of stream
14:56:39 [INFO] Reached end of stream
14:57:04 [INFO] Reached end of stream
14:57:29 [INFO] Reached end of stream
14:57:54 [INFO] Reached end of stream
14:58:19 [INFO] Reached end of stream
14:58:44 [INFO] Reached end of stream
14:59:09 [INFO] Reached end of stream
14:59:34 [INFO] Reached end of stream
14:59:59 [INFO] Reached end of stream
15:00:24 [INFO] Reached end of stream
15:00:49 [INFO] Reached end of stream
15:01:14 [INFO] Reached end of stream
15:01:39 [INFO] Reached end of stream
15:02:04 [INFO] Reached end of stream
15:02:29 [INFO] Reached end of stream
15:02:54 [INFO] Reached end of stream
15:03:19 [INFO] Reached end of stream
15:03:44 [INFO] Reached end of stream
15:04:09 [INFO] Reached end of stream
15:04:34 [INFO] Reached end of stream
15:04:59 [INFO] Reached end of stream
15:05:24 [INFO] Reached end of stream
15:05:49 [INFO] Reached end of stream
15:06:14 [INFO] Reached end of stream
15:06:39 [INFO] Reached end of stream
15:07:04 [INFO] Reached end of stream
15:07:29 [INFO] Reached end of stream
15:07:55 [INFO] Reached end of stream
15:08:20 [INFO] Reached end of stream
15:08:45 [INFO] Reached end of stream
15:09:10 [INFO] Reached end of stream
15:09:35 [INFO] Reached end of stream
15:10:00 [INFO] Reached end of stream
15:10:25 [INFO] Reached end of stream
15:10:50 [INFO] Reached end of stream
15:11:15 [INFO] Reached end of stream
15:11:43 [INFO] Reached end of stream
15:12:08 [INFO] Reached end of stream
15:12:33 [INFO] Reached end of stream
15:12:58 [INFO] Reached end of stream
15:13:23 [INFO] Reached end of stream
15:13:48 [INFO] Reached end of stream
15:14:13 [INFO] Reached end of stream
15:14:38 [INFO] Reached end of stream
15:15:03 [INFO] Reached end of stream
15:15:28 [INFO] Reached end of stream
15:15:53 [INFO] Reached end of stream
15:16:18 [INFO] Reached end of stream
15:16:43 [INFO] Reached end of stream
15:17:08 [INFO] Reached end of stream
15:17:33 [INFO] Reached end of stream
15:17:58 [INFO] Reached end of stream
15:18:23 [INFO] Reached end of stream
15:19:07 [INFO] Reached end of stream
15:26:22 [INFO] Reached end of stream
15:26:47 [INFO] Reached end of stream
15:27:12 [INFO] Reached end of stream
15:27:37 [INFO] Reached end of stream
15:28:02 [INFO] Reached end of stream
15:28:27 [INFO] Reached end of stream
15:28:52 [INFO] Reached end of stream
15:29:17 [INFO] Reached end of stream
15:29:42 [INFO] Reached end of stream
15:30:07 [INFO] Reached end of stream
15:30:32 [INFO] Reached end of stream
15:30:57 [INFO] Reached end of stream
15:31:22 [INFO] Reached end of stream
15:31:47 [INFO] Reached end of stream
15:32:12 [INFO] Reached end of stream
15:32:37 [INFO] Reached end of stream
15:33:02 [INFO] Reached end of stream

P.S. please tell me if a plugin is doing this or not.

 

Bump, this seems to be back. http://pastebin.com/rzAmSKxZ

 

Ladinn I'm confirming this, here is my (kinda same) error:

Code:

2012-03-30 22:02:29 [SEVERE] java.util.ConcurrentModificationException
2012-03-30 22:02:29 [SEVERE]    at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
2012-03-30 22:02:29 [SEVERE]    at java.util.AbstractList$Itr.next(AbstractList.java:343)
2012-03-30 22:02:29 [SEVERE]    at java.util.AbstractCollection.removeAll(AbstractCollection.java:336)
2012-03-30 22:02:29 [SEVERE]    at net.minecraft.server.World.tickEntities(World.java:1121)
2012-03-30 22:02:29 [SEVERE]    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:545)
2012-03-30 22:02:29 [SEVERE]    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:452)
2012-03-30 22:02:29 [SEVERE]    at net.minecraft.server.ThreadServerApplication.run(SourceFile:490)
2012-03-30 22:02:29 [SEVERE] Unexpected exception
java.util.ConcurrentModificationException
    at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
    at java.util.AbstractList$Itr.next(AbstractList.java:343)
    at java.util.AbstractCollection.removeAll(AbstractCollection.java:336)
    at net.minecraft.server.World.tickEntities(World.java:1121)
    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:545)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:452)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:490)
...and many end of streams

It looks like they got this bug in CB again (running dev build #2127)

 

Do you guys use orebfuscator I have the exact same error after I removed orebfuscator today it was gone.

 

Seems like vanilla minecraft is provoking that, not much we can do to help you if that's the case.