Any way to save state of Minecraft in case I die?

I am providing this answer based on the following assumption.

1. You are playing the world on hardcore mode.
2. You want to recover the world and continue on just as if you have died in survival.
3. You havent changed any mods/ updated the game since you first created your world.

If this is the case, there is a way. It would involve the following steps.

1. Obtain the seed of the world.
2. Create a new world using that seed with the same settings at this point you can change your world type to creative, survival or remain in hardcore.
3. Copy the newly generated world's level.dat and level.dat_old file over to the hardcore world.

This would essentially revive you as if you have died in survival.

Exact instructions can be found here

http://www.minecraftforum.net/forums/support/unmodified-minecraft-client/tutorials-and-faqs/1871629-how-to-save-your-world-after-death-in-hardcore

If you have a Mac you can enable Time Machine on your minecraft directory and your computer will make hourly backups. Your minecraft directory is ~/Library/Application Support/minecraft/

Another effective solution would be to use a backup mod. I reccomend Aroma Backup. It regularly creates a copy of your world file that can be restored any time. The only downside is that it only runs on an interval, so you could lose up to 30 minutes of progress.

"This is a very simple mod. It saves and backs up your world, so just in case some other mod corrups your world or a Supercharged Creeper explodes the key infrastructure of your base, you have a backup to restore your world from."

http://www.curse.com/mc-mods/minecraft/225658-aromabackup

If you're in hardcode, and you died, simply:

1. Spectate the world;
2. Open to LAN with cheats;
3. Type: /gamemode 1;
4. Goto where you died, (within 5 minutes, because they de-spawn);
5. Pickup those lost items;
6. Type: /gamemode 0;