---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 9/11/19, 1:43 PM
Description: Ticking block entity

java.util.ConcurrentModificationException
	at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1490)
	at java.base/java.util.HashMap$KeyIterator.next(HashMap.java:1513)
	at vk.a(SourceFile:1037)
	at bhr.a(SourceFile:233)
	at bvp.T_(SourceFile:338)
	at bhr.K(SourceFile:624)
	at vk.a(SourceFile:405)
	at net.minecraft.server.MinecraftServer.b(SourceFile:835)
	at net.minecraft.server.MinecraftServer.a(SourceFile:774)
	at eac.a(SourceFile:128)
	at net.minecraft.server.MinecraftServer.run(SourceFile:642)
	at java.base/java.lang.Thread.run(Thread.java:835)


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

-- Head --
Thread: Server thread
Stacktrace:
	at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1490)
	at java.base/java.util.HashMap$KeyIterator.next(HashMap.java:1513)
	at vk.a(SourceFile:1037)
	at bhr.a(SourceFile:233)
	at bvp.T_(SourceFile:338)

-- Block entity being ticked --
Details:
	Name: minecraft:piston // bvp
	Block: Block{minecraft:piston}[extended=false,facing=east]
	Block location: World: (-643,63,-956), Chunk: (at 13,3,4 in -41,-60; contains blocks -656,0,-960 to -641,255,-945), Region: (-2,-2; contains chunks -64,-64 to -33,-33, blocks -1024,0,-1024 to -513,255,-513)
	Block: Block{minecraft:piston}[extended=false,facing=east]
	Block location: World: (-643,63,-956), Chunk: (at 13,3,4 in -41,-60; contains blocks -656,0,-960 to -641,255,-945), Region: (-2,-2; contains chunks -64,-64 to -33,-33, blocks -1024,0,-1024 to -513,255,-513)
Stacktrace:
	at bhr.K(SourceFile:624)
	at vk.a(SourceFile:405)

-- Affected level --
Details:
	All players: 1 total; [vl['z0mbiesrock'/331, l='SSP world', x=-672.50, y=64.00, z=-995.50]]
	Chunk stats: ServerChunkCache: 3165
	Level dimension: minecraft:overworld
	Level name: SSP world
	Level seed: 611647601324458484
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: {}
	Level spawn location: World: (-32,67,-28), Chunk: (at 0,4,4 in -2,-2; contains blocks -32,0,-32 to -17,255,-17), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Level time: 32550284 game time, 40668779 day time
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 50903 (now: false), thunder time: 69704 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.b(SourceFile:835)
	at net.minecraft.server.MinecraftServer.a(SourceFile:774)
	at eac.a(SourceFile:128)
	at net.minecraft.server.MinecraftServer.run(SourceFile:642)
	at java.base/java.lang.Thread.run(Thread.java:835)

-- System Details --
Details:
	Minecraft Version: 1.14.4
	Minecraft Version ID: 1.14.4
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 12.0.2, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode, sharing), Oracle Corporation
	Memory: 1339565592 bytes (1277 MB) / 2147483648 bytes (2048 MB) up to 3221225472 bytes (3072 MB)
	CPUs: 2
	JVM Flags: 10 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx3G -Xms2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=30 -XX:G1ReservePercent=25 -XX:MaxGCPauseMillis=10 -XX:G1HeapRegionSize=32M
	Player Count: 1 / 8; [vl['z0mbiesrock'/331, l='SSP world', x=-672.50, y=64.00, z=-995.50]]
	Data Packs: vanilla
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.