java.util.ConcurrentModificationException
	at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:907)
	at java.util.ArrayList$Itr.next(ArrayList.java:857)
	at net.minecraft.server.v1_7_R4.Chunk.a(Chunk.java:897)
	at net.minecraft.server.v1_7_R4.World.getEntities(World.java:2705)
	at net.minecraft.server.v1_7_R4.World.getEntities(World.java:2692)
	at net.minecraft.server.v1_7_R4.World.getCubes(World.java:1301)
	at net.minecraft.server.v1_7_R4.Entity.move(Entity.java:521)
	at net.minecraft.server.v1_7_R4.EntityItem.h(EntityItem.java:83)
	at net.minecraft.server.v1_7_R4.World.entityJoinedWorld(World.java:1493)
	at net.minecraft.server.v1_7_R4.World.playerJoinedWorld(World.java:1459)
	at net.minecraft.server.v1_7_R4.World.lambda$tickEntities$1(World.java:1649)
	at net.minecraft.server.v1_7_R4.World.tickEntities(World.java:1664)
	at net.minecraft.server.v1_7_R4.WorldServer.tickEntities(WorldServer.java:528)
	at net.minecraft.server.v1_7_R4.MinecraftServer$1.run(MinecraftServer.java:758)
	at net.minecraft.server.v1_7_R4.MinecraftServer.v(MinecraftServer.java:786)
	at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:307)
	at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:641)
	at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:547)
	at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628)