While messing around with a data sorting and storage problem, this error started up.  It happens once a tick and I have no idea why, as none of the code I'm working with deals with living entities (although I do have four in my mod, none of them should be in the world and last I checked, they rendered just fine).

 

2013-06-22 17:37:17 [iNFO] [sTDERR] java.lang.NullPointerException
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.renderer.entity.RenderLiving.func_77031_a(RenderLiving.java:136)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.renderer.entity.RenderLiving.func_76986_a(RenderLiving.java:546)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.renderer.entity.RenderManager.func_78719_a(RenderManager.java:310)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.renderer.entity.RenderManager.func_78720_a(RenderManager.java:279)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.renderer.RenderGlobal.func_72713_a(RenderGlobal.java:508)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.renderer.EntityRenderer.func_78471_a(EntityRenderer.java:1150)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.renderer.EntityRenderer.func_78480_b(EntityRenderer.java:991)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:871)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at net.minecraft.client.Minecraft.run(Minecraft.java:760)
2013-06-22 17:37:17 [iNFO] [sTDERR] 	at java.lang.Thread.run(Unknown Source)

I sometimes face similar problems. I'd make multiple changes to my code and all of a sudden the ChunkCache class would error without any exception trace back to my methods.

 

The only approach I have to solving mysterious errors that appear completely unrelated is:

 

[*]Think: What the hell have I done?

[*]What did I change?

[*]Comment all changes

[*]Check if the error persists

[*]Comment more/less depending on result

[*]Repeat from 2.

 

It can take quite a while, but I don't think there's a better solution. It once took me 3 hours to find that one little damn line of code that ultimately caused the error - and it was a careless mistake. I smashed my head against the table...

I've got a Git repository I can backtrack to, it's just annoying as hell at this point to do so, because the error I was working on fixing spans three different classes.

 

Frak.

 

Edit:

Went back to my git version and still got the error.

I think it's that save that's fubar'd.

Edit:

Went back to my git version and still got the error.

I think it's that save that's fubar'd.

 

First thing I usually do when finding an error during development is to recreate the world. I don't care about bugs in development phase, since those have a chance to be caused by incompatible updates anyways...