If you try to give your self air repeatedly it will crash your game

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

Time: 9/27/13 9:59 PM
Description: Adding item to inventory

java.lang.NullPointerException
	at zi.g(SourceFile:151)
	at zi.i(SourceFile:171)
	at vd.a(SourceFile:234)
	at tq.b_(SourceFile:199)
	at vf.r(SourceFile:436)
	at vf.e(SourceFile:428)
	at pb.h(SourceFile:1194)
	at vf.h(SourceFile:211)
	at kq.i(SourceFile:204)
	at kv.a(SourceFile:201)
	at gs.a(SourceFile:136)
	at eb.b(SourceFile:63)
	at kv.e(SourceFile:69)
	at ky.b(SourceFile:40)
	at box.b(SourceFile:83)
	at net.minecraft.server.MinecraftServer.u(SourceFile:494)
	at net.minecraft.server.MinecraftServer.t(SourceFile:411)
	at bou.t(SourceFile:121)
	at net.minecraft.server.MinecraftServer.run(SourceFile:346)
	at jc.run(SourceFile:582)


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

-- Head --
Stacktrace:
	at zi.g(SourceFile:151)
	at zi.i(SourceFile:171)

-- Item being added --
Details:
	Item ID: 0
	Item data: 0
	Item name: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at vd.a(SourceFile:234)
	at tq.b_(SourceFile:199)
	at vf.r(SourceFile:436)
	at vf.e(SourceFile:428)
	at pb.h(SourceFile:1194)
	at vf.h(SourceFile:211)

-- Player being ticked --
Details:
	Entity Type: null (kq)
	Entity ID: 71
	Entity Name: green0003
	Entity's Exact location: 280.92, 4.00, -626.44
	Entity's Block location: World: (280,4,-627), Chunk: (at 8,0,13 in 17,-40; contains blocks 272,0,-640 to 287,255,-625), Region: (0,-2; contains chunks 0,-64 to 31,-33, blocks 0,0,-1024 to 511,255,-513)
	Entity's Momentum: 0.00, -0.08, 0.00
Stacktrace:
	at kq.i(SourceFile:204)
	at kv.a(SourceFile:201)
	at gs.a(SourceFile:136)
	at eb.b(SourceFile:63)
	at kv.e(SourceFile:69)

-- Ticking connection --
Details:
	Connection: kv@ecdede5
Stacktrace:
	at ky.b(SourceFile:40)
	at box.b(SourceFile:83)
	at net.minecraft.server.MinecraftServer.u(SourceFile:494)
	at net.minecraft.server.MinecraftServer.t(SourceFile:411)
	at bou.t(SourceFile:121)
	at net.minecraft.server.MinecraftServer.run(SourceFile:346)
	at jc.run(SourceFile:582)

-- System Details --
Details:
	Minecraft Version: 13w39b
	Operating System: Mac OS X (x86_64) version 10.8.4
	Java Version: 1.6.0_45, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 59621840 bytes (56 MB) / 137785344 bytes (131 MB) up to 1069416448 bytes (1019 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 1652 (92512 bytes; 0 MB) allocated, 1312 (73472 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 216 (12096 bytes; 0 MB) allocated, 163 (9128 bytes; 0 MB) used
	Player Count: 1 / 8; [kq['green0003'/71, l='Go Fish', x=280.92, y=4.00, z=-626.44]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.