Minecraft crashes when loading a World: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1

 ---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 16/03/14 1:59 PM
Description: Starting integrated server

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
	at com.google.gson.Gson.fromJson(Gson.java:815)
	at com.google.gson.Gson.fromJson(Gson.java:768)
	at oy.b(SourceFile:141)
	at oy.<init>(SourceFile:43)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:120)
	at cek.<init>(SourceFile:34)
	at bfr.a(SourceFile:1701)
	at bja.e(SourceFile:165)
	at bja.a(SourceFile:128)
	at biz.a(SourceFile:180)
	at biz.d(SourceFile:242)
	at biz.k(SourceFile:219)
	at bfr.p(SourceFile:1387)
	at bfr.ai(SourceFile:801)
	at bfr.f(SourceFile:755)
	at net.minecraft.client.main.Main.main(SourceFile:121)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
	at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:338)
	at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:79)
	at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
	at com.google.gson.Gson.fromJson(Gson.java:803)
	... 15 more


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

-- Head --
Stacktrace:
	at com.google.gson.Gson.fromJson(Gson.java:815)
	at com.google.gson.Gson.fromJson(Gson.java:768)
	at oy.b(SourceFile:141)
	at oy.<init>(SourceFile:43)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:120)
	at cek.<init>(SourceFile:34)

-- Starting integrated server --
Details:
	Level ID: 1_8 Snapshot
	Level Name: 1.8 Showcase
Stacktrace:
	at bfr.a(SourceFile:1701)
	at bja.e(SourceFile:165)
	at bja.a(SourceFile:128)
	at biz.a(SourceFile:180)
	at biz.d(SourceFile:242)
	at biz.k(SourceFile:219)

-- Affected screen --
Details:
	Screen name: bjk
Stacktrace:
	at bfr.p(SourceFile:1387)
	at bfr.ai(SourceFile:801)
	at bfr.f(SourceFile:755)
	at net.minecraft.client.main.Main.main(SourceFile:121)

-- System Details --
Details:
	Minecraft Version: 14w11b
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 56150808 bytes (53 MB) / 96677888 bytes (92 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 14w11b
	LWJGL: 2.9.1
	OpenGL: AMD Radeon HD 8610G + 8500M Dual Graphics GL version 4.3.12618 Compatibility Profile Context 13.251.0.0, ATI Technologies Inc.
	GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Anisotropic Filtering: Off (1)