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Unexpected exception java.lang.NullPointerException

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Posted 02 March 2011 - 06:40 PM

My friends and I were playing on our own server last night and my computer, which is running the server, ran out of battery. When I started it back up, all I did was try and turn the server on and I got this error.

[SEVERE] Unexpected exception
at cv.b(SourceFile:72)
at cp.a(SourceFile:1565)
at gd.d(SourceFile:461)
at fz.d(SourceFile:66)
at fz.b(SourceFile:87)
at cp.c(SourceFile:302)
at cp.a(SourceFile:259)
at cp.e(SourceFile:263)
at cp.a(SourceFile:200)
at mn.a(SourceFile:51)
at cp.(SourceFile:166)
at cv.(SourceFile:25)
at net.minecraft.server.MinecraftServer.a(SourceFile:169)
at net.minecraft.server.MinecraftServer.d(SourceFile:134)
at net.minecraft.server.MinecraftServer.run(SourceFile:237)
at bc.run(SourceFile:366)

What do I do? I tried starting a new map and it worked fine. We've been working on it for weeks and its at around 66 MB, so we really don't want to lose it. Is it possible the file is corrupted? I hope to god not....

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  • Location: USA

Posted 02 March 2011 - 06:45 PM


If you don't stop the server correctly, then it won't save chunks.

In the future, have your laptop plugged in.

I'm retired from this forum.



Posted 02 March 2011 - 06:50 PM

painfulleap said:

Do you have an old backup of your saves? If so use the level.dat and session.lock from there.

If you don't you can create a new world OVER the current one. It will not delete any previous chunks instead it will create a new spawn point in an unexplored area in your old map. Use a mapping program to find the location of your old buildings.

If chunks or other files do get corrupted the game will correct or overwrite them.

How do I do this?


  • Location: 0x00000000 (Every time you visit, a program dies.)
  • Minecraft: notch

Posted 02 March 2011 - 06:51 PM

You might try restoring the automatic backup. it is called level.dat_old, delete level.dat and replace it.

also, you don't need session.lock

I wrote a thread about this sort of stuff in the beta section.  if you can't fix it yourself, go there and I will take a shot at it.  It's called 'Official Corrupted Save Recovery Thread'



Posted 02 March 2011 - 06:59 PM

I'm gonna go ahead and tell everyone I really don't know much about running servers. All I know is I start the minecraft server program and then connect.  :o
In other words, explanations may be in order.

Thanks for the quick responses so far though.