Game crashes with superflat preset is above 256: java.lang.ArrayIndexOutOfBoundsException: 256

Well, Minecraft's maximum build height is 256, so when the game tries to place blocks above that, it crashes. Also, please don't give us the output of the console, but give us the crash report from
C:\Users\Logan\AppData\Roaming\.minecraft\crash-reports\crash-2014-08-18_17.17.46-server.txt
instead (the link to the crash report is always in the output). But I agree that Minecraft should not allow you to do this, instead of crashing.

Confirmed for

• Minecraft 1.8-pre 1

• Minecraft 1.8.1-pre3

Confirmed for

• 15w37a

  Example preset

  3;minecraft:bedrock,255*minecraft:dirt,minecraft:grass;1;

Error

[15:43:46] [Server thread/INFO]: Starting integrated minecraft server version 15w37a
[15:43:46] [Server thread/INFO]: Generating keypair
[15:43:47] [Server thread/ERROR]: Encountered an unexpected exception
java.lang.ArrayIndexOutOfBoundsException: 256
	at asc.<init>(SourceFile:101) ~[15w37a.jar:?]
	at arq.c(SourceFile:68) ~[15w37a.jar:?]
	at lk.m(SourceFile:695) ~[15w37a.jar:?]
	at lk.<init>(SourceFile:138) ~[15w37a.jar:?]
	at bvm.a(SourceFile:98) ~[15w37a.jar:?]
	at bvm.j(SourceFile:130) ~[15w37a.jar:?]
	at net.minecraft.server.MinecraftServer.run(SourceFile:420) [15w37a.jar:?]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]
[15:43:47] [Server thread/ERROR]: This crash report has been saved to: ###\crash-reports\crash-2015-09-11_15.43.47-server.txt
[15:43:47] [Server thread/INFO]: Stopping server
[15:43:47] [Server thread/INFO]: Saving players
[15:43:47] [Server thread/INFO]: Saving worlds
[15:43:47] [Server thread/ERROR]: Exception stopping the server
java.lang.NullPointerException
	at net.minecraft.server.MinecraftServer.u(SourceFile:393) ~[15w37a.jar:?]
	at bvm.u(SourceFile:323) ~[15w37a.jar:?]
	at net.minecraft.server.MinecraftServer.run(SourceFile:483) [15w37a.jar:?]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]

Server crash

---- Minecraft Crash Report ----
// Would you like a cupcake?

Time: 11.09.15 15:43
Description: Exception in server tick loop

java.lang.ArrayIndexOutOfBoundsException: 256
	at asc.<init>(SourceFile:101)
	at arq.c(SourceFile:68)
	at lk.m(SourceFile:695)
	at lk.<init>(SourceFile:138)
	at bvm.a(SourceFile:98)
	at bvm.j(SourceFile:130)
	at net.minecraft.server.MinecraftServer.run(SourceFile:420)
	at java.lang.Thread.run(Thread.java:745)


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

-- System Details --
Details:
	Minecraft Version: 15w37a
	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: 583688080 bytes (556 MB) / 786272256 bytes (749 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: 1, tcache: 1, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Player Count: 0 / 8; []
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

affect 1.13 release

Can no longer reproduce in 19w38b. Someone else please check. Didn't test it with 1.14.4.

Fixed in 1.14.4-pre1

Confirmed fixed; the blocks above it will have their count set to 0 (which makes sense and doesn't lose information)