Hopper: java.lang.NullPointerException

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-73562/

Crash:

java.lang.NullPointerException
	at java.util.HashMap.putAll(HashMap.java:498)
	at le.a(SourceFile:38)
	at hx.j(SourceFile:757)
	at kg.<init>(SourceFile:75)
	at hx.a(SourceFile:287)
	at bnj.b(SourceFile:67)
	at net.minecraft.server.MinecraftServer.t(SourceFile:481)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bng.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hs.run(SourceFile:575)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 9/5/13 3:52 PM
Description: Exception in server tick loop

java.lang.NullPointerException
	at java.util.HashMap.putAll(HashMap.java:498)
	at le.a(SourceFile:38)
	at hx.j(SourceFile:757)
	at kg.<init>(SourceFile:75)
	at hx.a(SourceFile:287)
	at bnj.b(SourceFile:67)
	at net.minecraft.server.MinecraftServer.t(SourceFile:481)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bng.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hs.run(SourceFile:575)


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

-- System Details --
Details:
	Minecraft Version: 13w36a
	Operating System: Mac OS X (x86_64) version 10.7.5
	Java Version: 1.6.0_51, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 16723192 bytes (15 MB) / 102297600 bytes (97 MB) up to 1065025536 bytes (1015 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 2529 (141624 bytes; 0 MB) allocated, 2529 (141624 bytes; 0 MB) used
	Suspicious classes: [com.ibm.icu.text.ArabicShapingException], [gnu.trove.TIntCollection], [gnu.trove.impl.HashFunctions, PrimeFinder], [gnu.trove.impl.hash.THash, TPrimitiveHash, TIntIntHash], [gnu.trove.iterator.TIterator, TAdvancingIterator, TIntIntIterator], [gnu.trove.map.TIntIntMap], [gnu.trove.map.hash.TIntIntHashMap], [gnu.trove.procedure.TIntIntProcedure], [gnu.trove.set.TIntSet]
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1312 (73472 bytes; 0 MB) allocated, 1312 (73472 bytes; 0 MB) used
	Player Count: 0 / 8; []
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-73562/8179099/