Ender Dragon Breath freezes server when under or above the world

After having this issue:

Please attach the complete output of the "Game Output (Your Minecraft name) " which can be found on the fourth tab of the launcher to this ticket.

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Confirmed for

• 15w36d It is hard to give any evidence as it seems like only the server stops responding, but the client still renders everything fine. There is nothing in the Game Output and trying a forced crash only causes Minecraft to stop responding but does not create a crash report.

Confirmed for 16w14a

---- Minecraft Crash Report ----
// You're mean.

Time: 2016/4/11 上午 12:21
Description: Ticking entity

java.lang.ArrayIndexOutOfBoundsException: 1
	at ayo.f(SourceFile:71)
	at xj.k(SourceFile:68)
	at xj.j(SourceFile:63)
	at xj.c(SourceFile:24)
	at wu.n(SourceFile:242)
	at sa.m(SourceFile:1619)
	at sb.m(SourceFile:276)
	at aht.a(SourceFile:1516)
	at lp.a(SourceFile:717)
	at aht.g(SourceFile:1494)
	at aht.k(SourceFile:1384)
	at lp.k(SourceFile:550)
	at net.minecraft.server.MinecraftServer.D(SourceFile:625)
	at net.minecraft.server.MinecraftServer.C(SourceFile:553)
	at byl.C(SourceFile:154)
	at net.minecraft.server.MinecraftServer.run(SourceFile:457)
	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 --
Stacktrace:
	at ayo.f(SourceFile:71)
	at xj.k(SourceFile:68)
	at xj.j(SourceFile:63)
	at xj.c(SourceFile:24)
	at wu.n(SourceFile:242)
	at sa.m(SourceFile:1619)
	at sb.m(SourceFile:276)
	at aht.a(SourceFile:1516)
	at lp.a(SourceFile:717)
	at aht.g(SourceFile:1494)

-- Entity being ticked --
Details:
	Entity Type: EnderDragon (wu)
	Entity ID: 111129
	Entity Name: Ender Dragon
	Entity's Exact location: 0.22, 255.71, -0.04
	Entity's Block location: World: (0,255,-1), Chunk: (at 0,15,15 in 0,-1; contains blocks 0,0,-16 to 15,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Entity's Momentum: -0.44, 1.52, -0.62
	Entity's Passengers: []
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at aht.k(SourceFile:1384)
	at lp.k(SourceFile:550)

-- Affected level --
Details:
	Level name: 16w14a
	All players: 1 total; [lr['Les3awe'/184, l='16w14a', x=2.34, y=255.88, z=3.01]]
	Chunk stats: ServerChunkCache: 1089 Drop: 0
	Level seed: 2205699959392962167
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (0,0,0), Chunk: (at 0,0,0 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: 0 game time, 0 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at net.minecraft.server.MinecraftServer.D(SourceFile:625)
	at net.minecraft.server.MinecraftServer.C(SourceFile:553)
	at byl.C(SourceFile:154)
	at net.minecraft.server.MinecraftServer.run(SourceFile:457)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 16w14a
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 189291440 bytes (180 MB) / 615915520 bytes (587 MB) up to 4253024256 bytes (4056 MB)
	JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx4G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn400M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Player Count: 1 / 8; [lr['Les3awe'/184, l='16w14a', x=2.34, y=255.88, z=3.01]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

This has resulted in the forever crash / Cannot enter of my world.

Could not reproduce on 1.11.1. I used /summon minecraft:ender_dragon ~ ~1 ~ {DragonPhase:0,Invulnerable:0,NoAI:0} to summon a dragon on a new superflat world, and let it fly to 0, 0 to use its breath attack. No crashes were observed with or without the bedrock floor- some of the breath fall through harmlessly and the rest disperse harmlessly on top.

Test video: https://youtu.be/qdbrgE6Olpo

Confirmed for 1.14 Pre-Release 5

Confirmed for 1.14 and 1.14.1 Pre-Release 1

Confirmed for 1.14.1 Pre-Release 2

Confirmed for 1.14.1

Fixed in 1.14.2 Pre-Release 1 (the ender dragon refuses to breathe into the void)