Code: Unexpected exception java.lang.NullPointerException at net.minecraft.server.WorldData.a(WorldData.java:128) at net.minecraft.server.WorldData.a(WorldData.java:122) at net.minecraft.server.WorldNBTStorage.saveWorldData(WorldNBTStorage.java:124) at net.minecraft.server.ServerNBTManager.saveWorldData(SourceFile:43) at net.minecraft.server.World.y(World.java:279) at net.minecraft.server.World.save(World.java:268) at net.minecraft.server.World.doTick(World.java:1739) at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:521) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:432) at net.minecraft.server.ThreadServerApplication.run(SourceFile:465) Is there any way I can fix the problem, because I can't even get into the server.