"java.lang.Throwable" spam in the console

Please give me a hint, why could I have this errors (?) in the console sometimes:

Code:

02:42:43 [INFO] Chunk (17, -16) stored at  (3, 22)
02:42:43 [INFO] net.minecraft.server.Chunk
02:42:43 [SEVERE] java.lang.Throwable
02:42:43 [SEVERE]       at net.minecraft.server.ChunkProviderServer.b(ChunkProviderServer.java:117)
02:42:43 [SEVERE]       at net.minecraft.server.World.c(World.java:202)
02:42:43 [SEVERE]       at net.minecraft.server.World.getTypeId(World.java:145)
02:42:43 [SEVERE]       at net.minecraft.server.BlockGrass.a(SourceFile:44)
02:42:43 [SEVERE]       at net.minecraft.server.World.h(World.java:1503)
02:42:43 [SEVERE]       at net.minecraft.server.World.g(World.java:1434)
02:42:43 [SEVERE]       at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:348)
02:42:43 [SEVERE]       at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:272)
02:42:43 [SEVERE]       at net.minecraft.server.ThreadServerApplication.run(SourceFile:366)
02:42:44 [INFO] Chunk (17, -16) stored at  (3, 22)
02:42:44 [SEVERE] java.lang.Throwable
02:42:44 [SEVERE]       at org.bukkit.craftbukkit.util.LongHashtable.get(LongHashtable.java:34)
02:42:44 [SEVERE]       at net.minecraft.server.ChunkProviderServer.b(ChunkProviderServer.java:109)
02:42:44 [SEVERE]       at net.minecraft.server.World.c(World.java:202)
02:42:44 [SEVERE]       at net.minecraft.server.World.getTypeId(World.java:145)
02:42:44 [SEVERE]       at net.minecraft.server.BlockGrass.a(SourceFile:44)
02:42:44 [SEVERE]       at net.minecraft.server.World.h(World.java:1503)
02:42:44 [SEVERE]       at net.minecraft.server.World.g(World.java:1434)
02:42:44 [SEVERE]       at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:348)
02:42:44 [SEVERE]       at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:272)
02:42:44 [SEVERE]       at net.minecraft.server.ThreadServerApplication.run(SourceFile:366)
02:42:44 [INFO] Chunk (17, -16) stored at  (3, 22)
02:42:44 [INFO] net.minecraft.server.Chunk
02:42:44 [SEVERE] java.lang.Throwable
02:42:44 [SEVERE]       at net.minecraft.server.ChunkProviderServer.b(ChunkProviderServer.java:117)
02:42:44 [SEVERE]       at net.minecraft.server.World.c(World.java:202)
02:42:44 [SEVERE]       at net.minecraft.server.World.getTypeId(World.java:145)
02:42:44 [SEVERE]       at net.minecraft.server.BlockGrass.a(SourceFile:44)
02:42:44 [SEVERE]       at net.minecraft.server.World.h(World.java:1503)
02:42:44 [SEVERE]       at net.minecraft.server.World.g(World.java:1434)
02:42:44 [SEVERE]       at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:348)
02:42:44 [SEVERE]       at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:272)
02:42:44 [SEVERE]       at net.minecraft.server.ThreadServerApplication.run(SourceFile:366)

 

This sometimes indicated a corrupted world.

 

Is there a way to fix it?
e.g. just delete the corrupted chunk to let CB re-generate it ?

 

Yes that should work if you can identify it.

 

Can you give an advice about a suitable tool to do this? (delete a chunk to make server re-create it)

 

I made an admin tool called Chunkster, it will fix the problem causing that error. You can find it in the tools section.