The bug
Due to MC-90423 the ender dragon will make the breath attack at the highest block at (0, 0)
, however if there is no block or if the block is at 255 the dragon tries to perform the breath attack there which will make the server unresponsive (freeze).
How to reproduce
Create a void world
Teleport to 0, 0
/tp 0 ~ 0
Remove the block below you if there is one
Summon an ender dragon
/summon ender_dragon ~ ~ ~ {DragonPhase:11}
Summon a boat near 0, 0
/summon boat 7 0 0 {NoGravity:1b,Invulnerable:1b}
Switch to Survival or Adventure mode and enter the boat
Punch the dragon when it is near you
Linked issues
is duplicated by 1
relates to 2
Comments 15


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 δΈε 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)
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.
If the launcher closes after game start, please edit your profile and select "Launcher visibility" then, "Keep the launcher open".