---- Minecraft Crash Report ----
// On the bright side, I bought you a teddy bear!
Time: 18.5.19 10.16
Description: Exception in server tick loop
java.lang.NullPointerException: Exception in server tick loop
 at bbx.a(SourceFile:479)
 at bqx.g(SourceFile:85)
 at bqx.<init>(SourceFile:60)
 at bpk.create(SourceFile:50)
 at bqn.n(SourceFile:81)
 at sk.p(SourceFile:598)
 at sk.<init>(SourceFile:131)
 at dhr.a(SourceFile:97)
 at dhr.d(SourceFile:132)
 at net.minecraft.server.MinecraftServer.run(SourceFile:502)
 at java.lang.Thread.run(Thread.java:748)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------
-- System Details --
Details:
 Minecraft Version: 18w20c
 Operating System: Linux (amd64) version 4.15.0-20-generic
 Java Version: 1.8.0_171, Oracle Corporation
 Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
 Memory: 202393552 bytes (193 MB) / 383983616 bytes (366 MB) up to 1060372480 bytes (1011 MB)
 JVM Flags: 5 total; -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
 Profiler Position: N/A (disabled)
 Player Count: 0 / 8; []
 Data Packs: vanilla
 Type: Integrated Server (map_client.txt)
 Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

[10:16:49] [Client thread/WARN]: Ambiguity between arguments [teleport, destination] and [teleport, targets] with inputs: [Player, 0123, @e, dd12be42-52a9-4a91-a8a1-11c01849e498]
[10:16:49] [Client thread/WARN]: Ambiguity between arguments [teleport, location] and [teleport, destination] with inputs: [0.1 -0.5 .9, 0 0 0]
[10:16:49] [Client thread/WARN]: Ambiguity between arguments [teleport, location] and [teleport, targets] with inputs: [0.1 -0.5 .9, 0 0 0]
[10:16:49] [Client thread/WARN]: Ambiguity between arguments [teleport, targets] and [teleport, destination] with inputs: [Player, 0123, dd12be42-52a9-4a91-a8a1-11c01849e498]
[10:16:49] [Client thread/WARN]: Ambiguity between arguments [teleport, targets, location] and [teleport, targets, destination] with inputs: [0.1 -0.5 .9, 0 0 0]
[10:16:49] [Client thread/INFO]: Loaded 0 recipes
[10:16:49] [Client thread/INFO]: Loaded 0 advancements
[10:16:49] [Server thread/INFO]: Starting integrated minecraft server version 18w20c
[10:16:49] [Server thread/INFO]: Generating keypair
[10:16:50] [Server thread/INFO]: Found new data pack vanilla, loading it automatically
[10:16:50] [Server thread/INFO]: Reloading ResourceManager: Default
[10:16:50] [Server thread/INFO]: Loaded 523 recipes
[10:16:51] [Server thread/INFO]: Loaded 570 advancements
[10:16:51] [Server thread/ERROR]: Encountered an unexpected exception
java.lang.NullPointerException: null
 at bbx.a(SourceFile:479) ~[18w20c.jar:?]
 at bqx.g(SourceFile:85) ~[18w20c.jar:?]
 at bqx.<init>(SourceFile:60) ~[18w20c.jar:?]
 at bpk.create(SourceFile:50) ~[18w20c.jar:?]
 at bqn.n(SourceFile:81) ~[18w20c.jar:?]
 at sk.p(SourceFile:598) ~[18w20c.jar:?]
 at sk.<init>(SourceFile:131) ~[18w20c.jar:?]
 at dhr.a(SourceFile:97) ~[18w20c.jar:?]
 at dhr.d(SourceFile:132) ~[18w20c.jar:?]
 at net.minecraft.server.MinecraftServer.run(SourceFile:502) [18w20c.jar:?]
 at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]
[10:16:51] [Server thread/ERROR]: This crash report has been saved to: /home/juozas/.minecraft/crash-reports/crash-2018-05-19_10.16.51-server.txt
[10:16:51] [Server thread/INFO]: Stopping server
[10:16:51] [Server thread/INFO]: Saving players
[10:16:51] [Server thread/INFO]: Saving worlds
[10:17:22] [Client Shutdown Thread/INFO]: Stopping server
[10:17:22] [Client Shutdown Thread/INFO]: Saving players
[10:17:22] [Client Shutdown Thread/INFO]: Saving worlds