Code: 15.11 01:24:50 [Server] INFO at net.minecraft.server.ThreadServerApplication.run(SourceFile:417) 15.11 01:24:50 [Server] INFO at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374) 15.11 01:24:50 [Server] INFO at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:467) 15.11 01:24:50 [Server] INFO at net.minecraft.server.World.tickEntities(World.java:1058) 15.11 01:24:50 [Server] INFO at java.util.AbstractCollection.removeAll(AbstractCollection.java:336) 15.11 01:24:50 [Server] INFO at java.util.AbstractList$Itr.next(AbstractList.java:343) 15.11 01:24:50 [Server] INFO at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372) 15.11 01:24:50 [Server] INFO java.util.ConcurrentModificationException 15.11 01:24:50 [Server] SEVERE Unexpected exception 15.11 01:24:50 [Server] SEVERE at net.minecraft.server.ThreadServerApplication.run(SourceFile:417) 15.11 01:24:50 [Server] SEVERE at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374) 15.11 01:24:50 [Server] SEVERE at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:467) 15.11 01:24:50 [Server] SEVERE at net.minecraft.server.World.tickEntities(World.java:1058) 15.11 01:24:50 [Server] SEVERE at java.util.AbstractCollection.removeAll(AbstractCollection.java:336) 15.11 01:24:50 [Server] SEVERE at java.util.AbstractList$Itr.next(AbstractList.java:343) 15.11 01:24:50 [Server] SEVERE at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372) 15.11 01:24:50 [Server] SEVERE java.util.ConcurrentModificationException This has happened twice, freezes the server and results in a read timeout. I've never seen this.
Error, caused most likely by either some really weird situation, or mob overload (if you have multiworlds). I'd try some mob limiting plugins, if the error occurs again.