---- Minecraft Crash Report ----
// Shall we play a game?

Time: 12/13/16 4:22 PM
Description: Exception ticking world

java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.remove(HashMap.java:1443)
	at lv.d(SourceFile:198)
	at lw.d(SourceFile:201)
	at net.minecraft.server.MinecraftServer.D(SourceFile:626)
	at net.minecraft.server.MinecraftServer.C(SourceFile:562)
	at cce.C(SourceFile:154)
	at net.minecraft.server.MinecraftServer.run(SourceFile:466)
	at java.lang.Thread.run(Thread.java:745)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Server thread
Stacktrace:
	at java.util.HashMap$HashIterator.remove(HashMap.java:1443)
	at lv.d(SourceFile:198)
	at lw.d(SourceFile:201)

-- Affected level --
Details:
	Level name: Some
	All players: 0 total; []
	Chunk stats: ServerChunkCache: 621 Drop: 333
	Level seed: 2555308349489401273
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-248,64,-88), Chunk: (at 8,4,8 in -16,-6; contains blocks -256,0,-96 to -241,255,-81), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Level time: 259125 game time, 5328 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 30604 (now: false), thunder time: 5099 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.D(SourceFile:626)
	at net.minecraft.server.MinecraftServer.C(SourceFile:562)
	at cce.C(SourceFile:154)
	at net.minecraft.server.MinecraftServer.run(SourceFile:466)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 1.11
	Operating System: Mac OS X (x86_64) version 10.11.6
	Java Version: 1.8.0_74, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 88831256 bytes (84 MB) / 284049408 bytes (270 MB) up to 1060372480 bytes (1011 MB)
	JVM Flags: 5 total; -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Player Count: 0 / 8; []
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.