Description: Saving entity NBT

java.lang.NullPointerException: Saving entity NBT
at net.minecraft.entity.Entity.func_70109_d(Entity.java:1345)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.setSpiritInstance(TileBoxOfEternalClosure.java:224)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.pullEntity(TileBoxOfEternalClosure.java:150)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.updateTileEntity(TileBoxOfEternalClosure.java:103)
at org.cyclops.cyclopscore.tileentity.CyclopsTileEntity.updateTicking(CyclopsTileEntity.java:86)
at org.cyclops.cyclopscore.tileentity.CyclopsTileEntity.access$000(CyclopsTileEntity.java:31)
at org.cyclops.cyclopscore.tileentity.CyclopsTileEntity$TickingTileComponent.func_73660_a(CyclopsTileEntity.java:283)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.func_73660_a(TileBoxOfEternalClosure.java:54)
at net.minecraft.world.World.func_72939_s(World.java:1718)
at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:545)
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:701)
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:344)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:605)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:481)
at java.lang.Thread.run(Unknown Source)

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

-- Head --
Stacktrace:
at net.minecraft.entity.Entity.func_70109_d(Entity.java:1345)

-- Entity being saved --
Details:
Entity Type: evilcraft.vengeanceSpirit (org.cyclops.evilcraft.entity.monster.VengeanceSpirit)
Entity ID: 34536
Entity Name: Vengeance Spirit
Entity's Exact location: 390.07, 67.26, 962.62
Entity's Block location: 390.00,67.00,962.00 - World: (390,67,962), Chunk: (at 6,4,2 in 24,60; contains blocks 384,0,960 to 399,255,975), Region: (0,1; contains chunks 0,32 to 31,63, blocks 0,0,512 to 511,255,1023)
Entity's Momentum: 0.00, 0.00, 0.00
Entity's Rider: ERROR NullPointerException: null
Entity's Vehicle: ERROR NullPointerException: null
Stacktrace:
at net.minecraft.entity.Entity.func_70109_d(Entity.java:1345)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.setSpiritInstance(TileBoxOfEternalClosure.java:224)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.pullEntity(TileBoxOfEternalClosure.java:150)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.updateTileEntity(TileBoxOfEternalClosure.java:103)
at org.cyclops.cyclopscore.tileentity.CyclopsTileEntity.updateTicking(CyclopsTileEntity.java:86)
at org.cyclops.cyclopscore.tileentity.CyclopsTileEntity.access$000(CyclopsTileEntity.java:31)
at org.cyclops.cyclopscore.tileentity.CyclopsTileEntity$TickingTileComponent.func_73660_a(CyclopsTileEntity.java:283)
at org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure.func_73660_a(TileBoxOfEternalClosure.java:54)

-- Block entity being ticked --
Details:
Name: boxOfEternalClosure // org.cyclops.evilcraft.tileentity.TileBoxOfEternalClosure
Block type: ID #988 (tile.blocks.evilcraft.boxOfEternalClosure // org.cyclops.evilcraft.block.BoxOfEternalClosure)
Block data value: 1 / 0x1 / 0b0001
Block location: World: (391,67,961), Chunk: (at 7,4,1 in 24,60; contains blocks 384,0,960 to 399,255,975), Region: (0,1; contains chunks 0,32 to 31,63, blocks 0,0,512 to 511,255,1023)
Actual block type: ID #988 (tile.blocks.evilcraft.boxOfEternalClosure // org.cyclops.evilcraft.block.BoxOfEternalClosure)
Actual block data value: 1 / 0x1 / 0b0001
Stacktrace:
at net.minecraft.world.World.func_72939_s(World.java:1718)
at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:545)

-- Affected level --
Details:
Level name: world
All players: 1 total; [EntityPlayerMP['Yoghurt4C'/34400, l='world', x=392.06, y=67.00, z=957.41]]
Chunk stats: ServerChunkCache: 824 Drop: 0
Level seed: -6881065225674408322
Level generator: ID 06 - RTG, ver 0. Features enabled: true
Level generator options:
Level spawn location: 0.00,64.00,0.00 - World: (0,64,0), Chunk: (at 0,4,0 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 17945101 game time, 18157106 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 1407 (now: true), thunder time: 69705 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:701)
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:344)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:605)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:481)
at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
Minecraft Version: 1.8.9
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_66, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation

It's strange that it worked a few times before crashing... I'll look into it, thanks for reporting this! :)

Thanks for reporting this.

Which EvilCraft version were you using?
What did you do that resulted in the crash?

latest (which is 0.9.3)
as it's said in the title, I tried to capture a vengeance spirit in an empty box.

Yes, ok, that was clear.
But which spirit were you trying to capture? From where did that spirit originate? How did you obtain the box?

the crash actually happened twice: the first time it was a cow, and the second time it was a white sheep. two different boxes were used.
the spirits originated from living mobs that got killed.
the first box came from a dungeon chest, and I've successfully used it 3 times before the crashes started happening for whatever reason. the second box was manually crafted and used "fresh".
the crashlogs are pretty much the same, except for mobs and coordinates.

I was not able to reproduce your crash, but I've added an extra check which should solve this eitherway.
@Yoghurt4C If you want, you can test the latest dev build. In that case, let me know if you still encounter the crash.