---- Minecraft Crash Report ----
// I let you down. Sorry :(

Time: 12/2/15 8:46 AM
Description: Colliding entity with block

java.util.ConcurrentModificationException
	at java.util.WeakHashMap$HashIterator.nextEntry(WeakHashMap.java:882)
	at java.util.WeakHashMap$KeyIterator.next(WeakHashMap.java:915)
	at vc.a(SourceFile:25)
	at ahn.a(SourceFile:373)
	at ahn.a(SourceFile:319)
	at ajh.a(SourceFile:129)
	at ajh.a(SourceFile:118)
	at ro.X(SourceFile:810)
	at ro.d(SourceFile:748)
	at rx.g(SourceFile:1463)
	at rx.n(SourceFile:1746)
	at ry.n(SourceFile:484)
	at yv.n(SourceFile:35)
	at zf.n(SourceFile:241)
	at rx.m(SourceFile:1579)
	at ry.m(SourceFile:275)
	at yv.m(SourceFile:40)
	at zf.m(SourceFile:297)
	at ahn.a(SourceFile:1467)
	at lp.a(SourceFile:719)
	at ahn.g(SourceFile:1445)
	at ahn.k(SourceFile:1335)
	at lp.k(SourceFile:552)
	at net.minecraft.server.MinecraftServer.D(SourceFile:625)
	at la.D(SourceFile:339)
	at net.minecraft.server.MinecraftServer.C(SourceFile:553)
	at net.minecraft.server.MinecraftServer.run(SourceFile:457)
	at java.lang.Thread.run(Thread.java:744)


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

-- Head --
Stacktrace:
	at java.util.WeakHashMap$HashIterator.nextEntry(WeakHashMap.java:882)
	at java.util.WeakHashMap$KeyIterator.next(WeakHashMap.java:915)
	at vc.a(SourceFile:25)
	at ahn.a(SourceFile:373)
	at ahn.a(SourceFile:319)
	at ajh.a(SourceFile:129)
	at ajh.a(SourceFile:118)

-- Block being collided with --
Details:
	Block: minecraft:stone_pressure_plate[powered=false]
	Block location: World: (595,57,360), Chunk: (at 3,3,8 in 37,22; contains blocks 592,0,352 to 607,255,367), Region: (1,0; contains chunks 32,0 to 63,31, blocks 512,0,0 to 1023,255,511)
Stacktrace:
	at ro.X(SourceFile:810)

-- Entity being checked for collision --
Details:
	Entity Type: Zombie (zf)
	Entity ID: 810
	Entity Name: Zombie
	Entity's Exact location: 594.84, 57.00, 360.70
	Entity's Block location: World: (594,57,360), Chunk: (at 2,3,8 in 37,22; contains blocks 592,0,352 to 607,255,367), Region: (1,0; contains chunks 32,0 to 63,31, blocks 512,0,0 to 1023,255,511)
	Entity's Momentum: 0.07, 0.00, 0.00
	Entity's Passengers: []
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at ro.d(SourceFile:748)
	at rx.g(SourceFile:1463)
	at rx.n(SourceFile:1746)
	at ry.n(SourceFile:484)
	at yv.n(SourceFile:35)
	at zf.n(SourceFile:241)
	at rx.m(SourceFile:1579)
	at ry.m(SourceFile:275)
	at yv.m(SourceFile:40)
	at zf.m(SourceFile:297)
	at ahn.a(SourceFile:1467)
	at lp.a(SourceFile:719)
	at ahn.g(SourceFile:1445)

-- Entity being ticked --
Details:
	Entity Type: Zombie (zf)
	Entity ID: 810
	Entity Name: Zombie
	Entity's Exact location: 594.84, 57.00, 360.70
	Entity's Block location: World: (594,57,360), Chunk: (at 2,3,8 in 37,22; contains blocks 592,0,352 to 607,255,367), Region: (1,0; contains chunks 32,0 to 63,31, blocks 512,0,0 to 1023,255,511)
	Entity's Momentum: 0.07, 0.00, 0.00
	Entity's Passengers: []
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at ahn.k(SourceFile:1335)
	at lp.k(SourceFile:552)

-- Affected level --
Details:
	Level name: world
	All players: 0 total; []
	Chunk stats: ServerChunkCache: 638 Drop: 0
	Level seed: 3599673377888481317
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (544,70,368), Chunk: (at 0,4,0 in 34,23; contains blocks 544,0,368 to 559,255,383), Region: (1,0; contains chunks 32,0 to 63,31, blocks 512,0,0 to 1023,255,511)
	Level time: 1097596468 game time, 3333401 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 2047 (now: false), thunder time: 74047 (now: false)
	Level game mode: Game mode: adventure (ID 2). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.D(SourceFile:625)
	at la.D(SourceFile:339)
	at net.minecraft.server.MinecraftServer.C(SourceFile:553)
	at net.minecraft.server.MinecraftServer.run(SourceFile:457)
	at java.lang.Thread.run(Thread.java:744)

-- System Details --
Details:
	Minecraft Version: 15w49a
	Operating System: Mac OS X (x86_64) version 10.11.1
	Java Version: 1.7.0_45, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 497385912 bytes (474 MB) / 1067974656 bytes (1018 MB) up to 1067974656 bytes (1018 MB)
	JVM Flags: 2 total; -Xmx1G -Xms1G
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Player Count: 0 / 20; []
	Is Modded: Unknown (can't tell)
	Type: Dedicated Server (map_server.txt)