The game crashed whilst exception in server tick loop
Error: java.util.concurrent.CompletionException: java.lang.AbstractMethodError: bxx$$Lambda$1063/1208288923.a(Lcom/mojang/datafixers/Dynamic;)Ljava/lang/Object;

---- Minecraft Crash Report ----
// I feel sad now :(

Time: 11/29/18 11:18 AM
Description: Ticking player

java.lang.AbstractMethodError: bxx$$Lambda$1072/1887701594.a(Lcom/mojang/datafixers/Dynamic;)Ljava/lang/Object;
	at yg.a(SourceFile:18)
	at cat.<init>(SourceFile:44)
	at bvl$a.<init>(SourceFile:29)
	at bxc$$Lambda$1010/1735717476.load(Unknown Source)
	at cax.a(SourceFile:86)
	at bqu.a(SourceFile:614)
	at bqu.a(SourceFile:229)
	at ui.d(SourceFile:439)
	at ui$$Lambda$2089/1460038899.get(Unknown Source)
	at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1582)
	at ui$$Lambda$2100/1818683220.accept(Unknown Source)
	at java.util.ArrayList.forEach(ArrayList.java:1249)
	at ui.e(SourceFile:369)
	at ui.a(SourceFile:272)
	at baq.a(SourceFile:261)
	at baq.d(SourceFile:256)
	at baq.b(SourceFile:497)
	at agi.a(SourceFile:770)
	at uz.a(SourceFile:798)
	at np.a(SourceFile:126)
	at np$b.a(SourceFile:18)
	at jq.a(SourceFile:15)
	at jq$$Lambda$2345/2070320572.run(Unknown Source)
	at qo.run(SourceFile:18)
	at net.minecraft.server.MinecraftServer.q(SourceFile:654)
	at net.minecraft.server.MinecraftServer.p(SourceFile:625)
	at net.minecraft.server.MinecraftServer.run(SourceFile:584)
	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 --
Thread: Server thread
Stacktrace:
	at yg.a(SourceFile:18)
	at cat.<init>(SourceFile:44)
	at bvl$a.<init>(SourceFile:29)
	at bxc$$Lambda$1010/1735717476.load(Unknown Source)
	at cax.a(SourceFile:86)
	at bqu.a(SourceFile:614)
	at bqu.a(SourceFile:229)
	at ui.d(SourceFile:439)
	at ui$$Lambda$2089/1460038899.get(Unknown Source)
	at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1582)
	at ui$$Lambda$2100/1818683220.accept(Unknown Source)
	at java.util.ArrayList.forEach(ArrayList.java:1249)
	at ui.e(SourceFile:369)
	at ui.a(SourceFile:272)
	at baq.a(SourceFile:261)
	at baq.d(SourceFile:256)
	at baq.b(SourceFile:497)
	at agi.a(SourceFile:770)
	at uz.a(SourceFile:798)
	at np.a(SourceFile:126)

-- Player being ticked --
Details:
	Entity Type: minecraft:player (ul)
	Entity ID: 392
	Entity Name: Ashtu
	Entity's Exact location: 1056.50, 65.00, 800.50
	Entity's Block location: World: (1056,65,800), Chunk: (at 0,4,0 in 66,50; contains blocks 1056,0,800 to 1071,255,815), Region: (2,1; contains chunks 64,32 to 95,63, blocks 1024,0,512 to 1535,255,1023)
	Entity's Momentum: 0.00, 0.00, 0.00
	Entity's Passengers: []
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at uj.n_(SourceFile:337)
	at baq.m_(SourceFile:1010)
	at uj.m_(SourceFile:311)
	at net.minecraft.server.MinecraftServer.b(SourceFile:787)
	at net.minecraft.server.MinecraftServer.a(SourceFile:716)
	at dog.a(SourceFile:128)
	at net.minecraft.server.MinecraftServer.run(SourceFile:582)
	at java.lang.Thread.run(Thread.java:745)

-- Affected level --
Details:
	Level name: 18w48a
	All players: 1 total; [ul['Ashtu'/392, l='18w48a', x=1056.50, y=65.00, z=800.50]]
	Chunk stats: ServerChunkCache: 4238
	Level seed: 4145532659335207515
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: {}
	Level spawn location: World: (16,72,96), Chunk: (at 0,4,0 in 1,6; contains blocks 16,0,96 to 31,255,111), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 17315 game time, 17315 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 68651 (now: false), thunder time: 59259 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true

-- System Details --
Details:
	Minecraft Version: 18w48a
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 862914560 bytes (822 MB) / 1610612736 bytes (1536 MB) up to 2147483648 bytes (2048 MB)
	JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
	Player Count: 1 / 8; [ul['Ashtu'/392, l='18w48a', x=1056.50, y=65.00, z=800.50]]
	Data Packs: vanilla
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.