Benjamin P. Esposti

I just had this bug occur. Has made one of my worlds unplayable (thankfully I hadn't done much in that world) as of right now. I was exploring and the game suddenly crashed. When I tried to re-enter the world, it causes the game to crash after just a few seconds, with the same error.

The crash appears to occur in a Forest (possibly ForestHills) biome, if that even matters.

Details:
Minecraft 1.11 (Vanilla, for PC - un-modded)
Windows 7 x86 v6.1
Java Version: 1.7.0_79
Memory: 79430696 bytes (75 MB) / 336797696 bytes (321 MB) up to 523501568 bytes (499 MB)

World details:
Seed: -3362653853311474883
Gamemode: 0 (Survival)
Difficulty: Peaceful
Cheats: true (Though I haven't cheated - yet, lol. I don't usually cheat. In fact, I dunno why I even set it to true. XD)
Level generator: ID 02 - largeBiomes, ver 0. Features enabled: true
Level generator options: (nothing)

Here is the beginning of the rather long stack trace:

java.lang.StackOverflowError: Exception while updating neighbours
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
	at ajq.a(SourceFile:474)
	at ajq.b(SourceFile:430)
	at amz.b(SourceFile:83)
	at lw.a(SourceFile:499)
	at lw.a(SourceFile:483)
	at amz.c(SourceFile:232)
	at aum.a(SourceFile:486)
	at ajq.a(SourceFile:320)
	at aqy.f(SourceFile:31)
	at aqy.a(SourceFile:25)
	at atk$a.a(SourceFile:418)
	at ajq.a(SourceFile:469)
	at ajq.b(SourceFile:431)
	at amz.b(SourceFile:83)
	at lw.a(SourceFile:499)
	at lw.a(SourceFile:483)
	at amz.c(SourceFile:232)
	at aum.a(SourceFile:486)
	at ajq.a(SourceFile:320)
	at aqy.f(SourceFile:31)
	at aqy.a(SourceFile:25)
        ...(continued)...

There is more stack trace:

-- Head --
Thread: Server thread
Stacktrace:
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=2]
	Block location: World: (-140,16,-1126), Chunk: (at 4,1,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)
Stacktrace:
	at ajq.a(SourceFile:472)
	at ajq.b(SourceFile:431)
	at amz.b(SourceFile:83)
	at lw.a(SourceFile:499)
	at lw.a(SourceFile:483)
	at amz.c(SourceFile:232)
	at aum.a(SourceFile:486)
	at ajq.a(SourceFile:320)
	at aqy.f(SourceFile:31)
	at aqy.a(SourceFile:25)
	at atk$a.a(SourceFile:418)
	at ajq.a(SourceFile:469)
	at ajq.b(SourceFile:430)
	at amz.b(SourceFile:83)
        ...(continued)...

Finally, after a lot of stack trace lines in the error log, there is some more printout indicating what blocks were being updated. The last few seem to be the important ones, as all the others appear to have a "source block type" of tile.water and a "block" of minecraft:water. (I go into detail later on...)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=1]
	Block location: World: (-141,16,-1126), Chunk: (at 3,1,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=14]
	Block location: World: (-140,16,-1126), Chunk: (at 4,1,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=15]
	Block location: World: (-141,16,-1126), Chunk: (at 3,1,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=7]
	Block location: World: (-141,17,-1126), Chunk: (at 3,1,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

*...(snipped to shorten comment)...*

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=5]
	Block location: World: (-140,37,-1127), Chunk: (at 4,2,9 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=4]
	Block location: World: (-140,37,-1126), Chunk: (at 4,2,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=3]
	Block location: World: (-140,37,-1127), Chunk: (at 4,2,9 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=2]
	Block location: World: (-140,37,-1126), Chunk: (at 4,2,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=1]
	Block location: World: (-140,37,-1127), Chunk: (at 4,2,9 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #8 (tile.water // amz)
	Block: minecraft:water[level=10]
	Block location: World: (-141,37,-1127), Chunk: (at 3,2,9 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #10 (tile.lava // amz)
	Block: minecraft:water[level=10]
	Block location: World: (-141,38,-1127), Chunk: (at 3,2,9 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #10 (tile.lava // amz)
	Block: minecraft:lava[level=10]
	Block location: World: (-140,39,-1127), Chunk: (at 4,2,9 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #9 (tile.water // aqy)
	Block: minecraft:lava[level=10]
	Block location: World: (-140,39,-1127), Chunk: (at 4,2,9 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

-- Block being updated --
Details:
	Source block type: ID #9 (tile.water // aqy)
	Block: minecraft:lava[level=10]
	Block location: World: (-140,48,-1126), Chunk: (at 4,3,10 in -9,-71; contains blocks -144,0,-1136 to -129,255,-1121), Region: (-1,-3; contains chunks -32,-96 to -1,-65, blocks -512,0,-1536 to -1,255,-1025)

From what I can tell, it appears that there might be some issue with water and lava touching each other, but I don't know for sure. I suspect this, because the X and Z coords don't vary more than about +-1 block, however the fact that the water blocks appear to be in a column (along Y axis) tells me that this might be in a ravine or large cave, where water has flowed straight down.

Also note that most of the water block update reports are for "source block type" ID #8 (flowing water), while there are two reports containing "source block type" ID #9 (still water). The two lava block update report "source block type" are both ID #10 (flowing lava).

In addition, my water+lava mixing/touching theory is supported by the fact that the last two block update reports show the "source block type" being water, but the "block" is lava. Also, one of the block update reports with a "source block type" of lava has "block" as water (the other one is lava).
Yet another supporting fact is that the error hints to a stack overflow error while updating neighbours. But, having done some coding/programming before, I know that unfortunately, this could possibly be irrelevant to the actual source of the error! XD

Conclusion: It appears as though the script might be "fighting" to figure out whether water or lava should flow within a certain block; Specifically, the block at (-140, 39, -1127).

I can post a full crash log(s) if you wish - I just don't know how to add an attachment to this comment (if it's even possible).

Hope this helps,
-Ben

P.S. I was also able to reproduce this again by generating a completely new world with the same seed, and by going to the same location (or, at least close enough to load the chunk(s) where the problem blocks lie).