Looking to create a void world in the new Minecraft 1.8, but the old void world code is no longer working for you also?
Here is how to make the most useful superflat preset available.
The new flatland generation in 1.8 is a bit different,
Create your new world as usual:


Make sure the Game Mode is set to Creative and click on More World Options...


Set Generate Structures to OFF, World Type to Superflat, Allow Cheats to ON, and Bonus Chest the default OFF. Then click on Customize located under World Type.


Delete the default preset code and fill it in with "3;minecraft:air;1;village" or just "3;minecraft:air" and it will set it to the default (image above) code automatically. Once you have clicked done and generated your world, when you spawn into your newly made void world, double tap space and fly up to at least y-coord (1). You can see your coordinates by pressing F3 and F3 to close out of them again.

To make a starting platform to build on, find a spot for your platform, and while in creative mode type in: "/setblock ~ ~ ~ minecraft:bedrock"


From that platform you can begin building the next viral Skyblock game or an adventure map, or just a testing platform for texture and skin creation. Hope this helps! Thanks.