Ticking entity / java.lang.ClassCastException: fn cannot be cast to java.lang.Boolean

Does MC-124460 fix your problem? If not, please attach the crash report found in [minecraft/crash-reports/crash-<DATE>-client.txt|http://hopper.minecraft.net/help/guides/finding-minecraft-data-folder] here. If you cannot find a crash report, please attach the full launcher log found in [minecraft/launcher_log.txt|http://hopper.minecraft.net/help/guides/minecraft-logs/].

Minecraft Crash Report ----
// Don't be sad. I'll do better next time, I promise!

Time: 5/18/19 9:53 AM
Description: Ticking entity

java.lang.ClassCastException: fn cannot be cast to java.lang.Boolean
at aig.i(SourceFile:76)
at aqs.k(SourceFile:48)
at air.h(SourceFile:2102)
at ais.h(SourceFile:293)
at dhn.a(SourceFile:165)
at dhn$$Lambda$1953/1640043321.accept(Unknown Source)
at bhi.a(SourceFile:676)
at dhn.d(SourceFile:134)
at cvk.m(SourceFile:1433)
at cvk.e(SourceFile:925)
at cvk.b(SourceFile:411)
at net.minecraft.client.main.Main.main(SourceFile:154)

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

– Head –
Thread: Client thread
Stacktrace:
at aig.i(SourceFile:76)
at aqs.k(SourceFile:48)
at air.h(SourceFile:2102)
at ais.h(SourceFile:293)
at dhn.a(SourceFile:165)
at dhn$$Lambda$1953/1640043321.accept(Unknown Source)

– Entity being ticked –
Details:
Entity Type: minecraft:pig (arf)
Entity ID: 3962311
Entity Name: Pig
Entity's Exact location: 1.06, 65.59, -1.78
Entity's Block location: World: (1,65,-2), Chunk: (at 1,4,14 in 0,-1; contains blocks 0,0,-16 to 15,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Entity's Momentum: -0.09, -0.08, -0.04
Entity's Passengers: []
Entity's Vehicle: ~_ERROR~ NullPointerException: null
Stacktrace:
at bhi.a(SourceFile:676)
at dhn.d(SourceFile:134)

– Affected level –
Details:
Level name: MpServer
All players: 54 total; [djx['Andrewx3421m'/254030, l='MpServer', x=-7.21, y=69.00, z=0.28], djy['sullentaki'/3963068, l='MpServer', x=-6.41, y=67.00, z=-4.31], djy['Narone'/3951229, l='MpServer', x=-12.41, y=69.00, z=-22.19], djy['Hase222'/3959547, l='MpServer', x=-25.25, y=70.00, z=1.44], djy['Iman2002'/3959533, l='MpServer', x=-25.50, y=70.00, z=1.38], djy['Xander10J'/3961540, l='MpServer', x=-24.03, y=70.03, z=1.56], djy['KonimariPL'/3962773, l='MpServer', x=-25.22, y=70.00, z=1.94], djy['Brashke'/3952968, l='MpServer', x=-11.50, y=67.00, z=0.56], djy['Mudsta'/3962307, l='MpServer', x=-7.03, y=70.03, z=0.31], djy['VerCzit'/3954583, l='MpServer', x=-7.35, y=68.07, z=9.72], djy['KawaiiBella_'/3963091, l='MpServer', x=-24.47, y=70.00, z=0.53], djy['Jellyjdz'/3961168, l='MpServer', x=-41.25, y=73.00, z=-6.75], djy['fbenedetta'/3963070, l='MpServer', x=-5.69, y=86.05, z=-0.56], djy['Noemissius'/3963085, l='MpServer', x=-5.41, y=85.03, z=-0.91], djy['Blue_Bolt7'/3959549, l='MpServer', x=-25.16, y=70.00, z=-0.91], djy['IseifOu_dZ'/3962775, l='MpServer', x=-24.00, y=70.00, z=-0.22], djy['2bue62m4g2'/55, l='MpServer', x=-8.50, y=67.00, z=-4.50], djy['49tr2qn88b'/59, l='MpServer', x=-12.00, y=67.00, z=-8.00], djy['31_nico'/3959540, l='MpServer', x=-9.88, y=67.00, z=-4.84], djy['Phylos096'/3959741, l='MpServer', x=24.50, y=72.16, z=10.69], djy['W0lf1ng99'/3961747, l='MpServer', x=-5.06, y=75.00, z=-2.00], djy['Detrusion'/3958486, l='MpServer', x=26.22, y=72.00, z=-4.84], djy['NEOTHEATER'/3962777, l='MpServer', x=24.48, y=71.03, z=-9.64], djy['2r1qz0t647'/0, l='MpServer', x=3.50, y=67.00, z=-14.50], djy['306zezt5y6'/6, l='MpServer', x=3.50, y=68.00, z=-2.50], djy['1mmt2u5rvr'/8, l='MpServer', x=-0.50, y=68.00, z=-8.50], djy['5zoigglx78'/9, l='MpServer', x=1.50, y=68.00, z=-5.50], djy['simo88royale'/3963095, l='MpServer', x=-7.41, y=69.78, z=0.25], djy['kb8u4e2hrt'/1, l='MpServer', x=10.50, y=67.00, z=0.50], djy['690k9brs34'/2, l='MpServer', x=1.50, y=68.00, z=6.50], djy['7oz9upk467'/4, l='MpServer', x=-0.50, y=68.00, z=9.50], djy['59655kw78m'/7, l='MpServer', x=3.50, y=68.00, z=3.50], djy['CharlesJohn'/3946809, l='MpServer', x=-41.56, y=85.49, z=60.08], djy['Sacha_ltcs'/3950441, l='MpServer', x=-25.61, y=72.51, z=-37.49], djy['lop033'/3958491, l='MpServer', x=-25.47, y=71.09, z=-28.19], djy['YanM82'/3944492, l='MpServer', x=-34.98, y=72.27, z=-64.02], djy['Whitegard'/3948003, l='MpServer', x=-43.22, y=89.08, z=-41.00], djy['alccap'/3963646, l='MpServer', x=-23.84, y=70.00, z=0.03], djy['PoppyTheGreat'/3963740, l='MpServer', x=-26.78, y=74.53, z=0.59], djy['Comple_bubik'/3963089, l='MpServer', x=-7.16, y=69.67, z=0.22], djy['alvnmi'/3951022, l='MpServer', x=17.77, y=70.06, z=13.31], djy['MindQuad'/3958875, l='MpServer', x=3.50, y=67.00, z=-9.03], djy['Holzwein'/3964192, l='MpServer', x=-8.66, y=67.97, z=-7.44], djy['Sharksfan07'/3964194, l='MpServer', x=-23.56, y=70.00, z=1.13], djy['FreddyCracker'/3964196, l='MpServer', x=-10.76, y=67.00, z=-1.19], djy['Jonthebeast22'/3964198, l='MpServer', x=-24.16, y=70.00, z=-0.41], djy['Spongebob_567'/3963079, l='MpServer', x=-5.59, y=94.56, z=-0.94], djy['Adriann_Gay'/3963072, l='MpServer', x=-4.56, y=84.17, z=-0.47], djy['0_Palmer_0'/3962310, l='MpServer', x=-7.56, y=68.00, z=-7.72], djy['Alex_is_trash'/3964383, l='MpServer', x=-23.13, y=70.03, z=0.41], djy['TLT222'/3964385, l='MpServer', x=-23.59, y=70.03, z=1.50], djy['NewAccount1'/3964387, l='MpServer', x=-24.22, y=70.03, z=1.72], djy['Jas5Fire'/3959551, l='MpServer', x=-2.36, y=68.34, z=13.33], djy['captportugal'/3963093, l='MpServer', x=-3.06, y=67.00, z=-5.72]]
Chunk stats: MultiplayerChunkCache: 5041, 169
Level seed: 0
Level generator: ID 01 - flat, ver 0. Features enabled: false
Level generator options: {}
Level spawn location: World: (-26,70,-1), Chunk: (at 6,4,15 in -2,-1; contains blocks -32,0,-16 to -17,255,-1), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
Level time: 227105881 game time, 389000 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Server brand: vanilla
Server type: Non-integrated multiplayer server
Stacktrace:
at dhn.a(SourceFile:421)
at cvk.b(SourceFile:1923)
at cvk.b(SourceFile:426)
at net.minecraft.client.main.Main.main(SourceFile:154)

– System Details –
Details:
Minecraft Version: 1.14.1
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: 950970168 bytes (906 MB) / 1912602624 bytes (1824 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
Launched Version: 1.14.1
LWJGL: 3.2.1 build 12
OpenGL: GeForce GTX 660/PCIe/SSE2 GL version 4.6.0 NVIDIA 391.35, NVIDIA Corporation
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: Yes
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: vanilla, file/Faithful+1.13.2-rv2.zip
Current Language: English (US)
CPU: 8x Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz

what do I do with the information given?

I still can't do anything 

what does anything of this mean?

how can it help me?

Looks like a pig was riding something that was destroyed from under it (like a boat or a mine cart).  This used to be a problem with killing a Ravager's rider in earlier builds.

This is the problem:  Entity's Vehicle: ~_ERROR~ NullPointerException: null

If you are desperate you can always edit the dat file and remove the affected entity or correct its entry.

bruh this literally does not help me at all. I need like an actual guide on these things. 

I'm still stuck is what I'm trying to say.

I don't know how to access dat files, and I am not able to get in the game, like, my problem gets to a point that I am never able to see the Mojang screen.

I really need help.

sorry for being so idiotic on these things...

This issue was probably caused by incompatible data from modded server. Anyway, that code was changed some time ago and no longer crashes.