So, I am working on some code, and the crash I am getting looks like this:

[19:18:58] [server thread/ERROR]: Encountered an unexpected exception
java.lang.NullPointerException
at net.minecraft.crash.CrashReportCategory.firstTwoElementsOfStackTraceMatch(Unknown Source) ~[CrashReportCategory.class:?]
at net.minecraft.crash.CrashReport.makeCategoryDepth(Unknown Source) ~[CrashReport.class:?]
at net.minecraft.world.World.addWorldInfoToCrashReport(Unknown Source) ~[World.class:?]
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(Unknown Source) ~[MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.tick(Unknown Source) ~[MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.tick(Unknown Source) ~[integratedServer.class:?]
at net.minecraft.server.MinecraftServer.run(Unknown Source) [MinecraftServer.class:?]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_51]

So it looks like it is crashing while trying to print the reason it is crashing. Any suggestions on how to track down the cause of one of these crashes?

Well, you could work with breakpoints and see after what operation it crashes, thet would narrow down possibilities and tell where to look.

 

More important questions would be - when did this started happning? Do you have versioning (working backups)?

 

If you can't think of ANY place this can be coming from I suggest commenting out parts of your mod and test if it works without it. (start with tick events, entities, tile entities (onUpdate() method mostly).

Using the latest snapshot of ForgeGradle instead of the 2.0.1 stable version may help, since the snapshot includes a recent fix that correctly builds Minecraft with debug information which was previously missing.

 

To switch to the snapshot, follow the instructions in the comments at the top of build.gradle (you may need to download a recent MDK version and copy the code from its build.gradle if you deleted the comments from yours).