---- Minecraft Crash Report ----
// Oh - I know what I did wrong!

Time: 28.07.14 13:16
Description: Exception in server tick loop

java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
	at java.util.HashMap$KeyIterator.next(Unknown Source)
	at qf.b(SourceFile:150)
	at qh.b(SourceFile:35)
	at aqa.b(SourceFile:894)
	at ql.b(SourceFile:808)
	at aqa.e(SourceFile:909)
	at sf.e(SourceFile:299)
	at rb.a(SourceFile:532)
	at gp.l(SourceFile:328)
	at qu.c(SourceFile:144)
	at net.minecraft.server.MinecraftServer.y(SourceFile:623)
	at net.minecraft.server.MinecraftServer.x(SourceFile:529)
	at cwp.x(SourceFile:144)
	at net.minecraft.server.MinecraftServer.run(SourceFile:445)
	at java.lang.Thread.run(Unknown Source)


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

-- System Details --
Details:
	Minecraft Version: 14w30c
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.6.0_45, Sun Microsystems Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Sun Microsystems Inc.
	Memory: 503661056 bytes (480 MB) / 805060608 bytes (767 MB) up to 1060372480 bytes (1011 MB)
	JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	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.