Off course 4J is not referring to the Mayan’s prophecy of the world ending in 2012. In Minecraft The End is a floating island which is made up of a material known as End Stone. Endermen can be found in this area quite easily as it carries a high spawn rate. Also the plane is guarded by a boss creature called Ender Dragon.
Here is what the developers wrote:
We have a good bit more work to do on The End, and don’t want that to hold up TU7. The End will be in TU8.
However, before that, we’ll be getting Update 7 which was revealed last week. It is going to feature animal breeding, potion brewing, experience points, enchantment tables, mushroom biomes, a Nether Fortress, a new tutorial world, villagers, mooshrooms, blaze, snow golems, magma cubes and baby animals.
4J has not announced a release date for either update.