---- Minecraft Crash Report ----
// Don't do that.

Time: 19.05.16 16:04
Description: Executing command block

java.lang.NullPointerException: Executing command block
	at rv.a(SourceFile:324)
	at p$1.a(SourceFile:188)
	at p$1.apply(SourceFile:185)
	at com.google.common.base.Predicates$AndPredicate.apply(Predicates.java:359)
	at com.google.common.base.Predicates$AndPredicate.apply(Predicates.java:359)
	at aia.a(SourceFile:2283)
	at p.a(SourceFile:490)
	at p.b(SourceFile:143)
	at k.a(SourceFile:51)
	at ahp.a(SourceFile:114)
	at aku.b(SourceFile:96)
	at lr.a(SourceFile:645)
	at lr.d(SourceFile:216)
	at net.minecraft.server.MinecraftServer.D(SourceFile:618)
	at net.minecraft.server.MinecraftServer.C(SourceFile:554)
	at bzg.C(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:458)
	at java.lang.Thread.run(Thread.java:745)


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

-- Head --
Thread: Server thread
Stacktrace:
	at rv.a(SourceFile:324)
	at p$1.a(SourceFile:188)
	at p$1.apply(SourceFile:185)
	at com.google.common.base.Predicates$AndPredicate.apply(Predicates.java:359)
	at com.google.common.base.Predicates$AndPredicate.apply(Predicates.java:359)
	at aia.a(SourceFile:2283)
	at p.a(SourceFile:490)
	at p.b(SourceFile:143)
	at k.a(SourceFile:51)

-- Command to be executed --
Details:
	Command: /entitydata @e[type=!Player] {CustomName:"Test",CustomNameVisible:1b}
	Name: @
Stacktrace:
	at ahp.a(SourceFile:114)
	at aku.b(SourceFile:96)

-- Block being ticked --
Details:
	Block: minecraft:repeating_command_block[conditional=false,facing=north]
	Block location: World: (6,4,6), Chunk: (at 6,0,6 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Stacktrace:
	at lr.a(SourceFile:645)
	at lr.d(SourceFile:216)

-- Affected level --
Details:
	Level name: New World
	All players: 1 total; [lt['Marcono1234'/2, l='New World', x=4,67, y=4,00, z=5,65]]
	Chunk stats: ServerChunkCache: 625 Drop: 0
	Level seed: -6783626917757943078
	Level generator: ID 01 - flat, ver 0. Features enabled: true
	Level generator options: 3;minecraft:air;127;decoration
	Level spawn location: World: (8,4,8), Chunk: (at 8,0,8 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 539 game time, 539 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 67662 (now: false), thunder time: 110022 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.D(SourceFile:618)
	at net.minecraft.server.MinecraftServer.C(SourceFile:554)
	at bzg.C(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:458)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 16w20a
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.8.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 154691800 bytes (147 MB) / 269787136 bytes (257 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: 1 / 8; [lt['Marcono1234'/2, l='New World', x=4,67, y=4,00, z=5,65]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.