crash

Minecraft Crash Report ----
// Why did you do that?

Time: 06/12/14 下午 08:39
Description: Exception ticking world

java.lang.RuntimeException: Already decorating
at arv.a(SourceFile:25)
at arj.a(SourceFile:389)
at ask.a(SourceFile:85)
at bgt.a(SourceFile:472)
at qt.a(SourceFile:174)
at bff.a(SourceFile:872)
at qt.c(SourceFile:104)
at qt.d(SourceFile:116)
at aqr.a(SourceFile:276)
at qu.h(SourceFile:327)
at qu.c(SourceFile:202)
at net.minecraft.server.MinecraftServer.A(SourceFile:600)
at net.minecraft.server.MinecraftServer.z(SourceFile:532)
at cyk.z(SourceFile:155)
at net.minecraft.server.MinecraftServer.run(SourceFile:448)
at java.lang.Thread.run(Unknown Source)

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

– Head –
Stacktrace:
at arv.a(SourceFile:25)
at arj.a(SourceFile:389)
at ask.a(SourceFile:85)
at bgt.a(SourceFile:472)
at qt.a(SourceFile:174)
at bff.a(SourceFile:872)
at qt.c(SourceFile:104)
at qt.d(SourceFile:116)
at aqr.a(SourceFile:276)
at qu.h(SourceFile:327)
at qu.c(SourceFile:202)

– Affected level –
Details:
Level name: hohohoho
All players: 1 total; [qx['LemonMing'/281, l='hohohoho', x=272.11, y=72.68, z=-97.48]]
Chunk stats: ServerChunkCache: 1329 Drop: 0
Level seed: -5080881946598922406
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: 141.00,64.00,191.00 - World: (141,64,191), Chunk: (at 13,4,15 in 8,11; contains blocks 128,0,176 to 143,255,191), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 132072 game time, 25595 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 10513 (now: false), thunder time: 29969 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true
Stacktrace:
at net.minecraft.server.MinecraftServer.A(SourceFile:600)
at net.minecraft.server.MinecraftServer.z(SourceFile:532)
at cyk.z(SourceFile:155)
at net.minecraft.server.MinecraftServer.run(SourceFile:448)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 1.8.1
Operating System: Windows 8.1 (x86) version 6.3
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 170589824 bytes (162 MB) / 523501568 bytes (499 MB) up to 523501568 bytes (499 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [qx['LemonMing'/281, l='hohohoho', x=272.11, y=72.68, z=-97.48]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.