Minecraft:Java Edition Classic 0.0.12a

0.0.12a<ref>Template:Twon</ref> is a version of Minecraft:Java Edition Classic released on May 19, 2009, at 22:36 UTC,<ref>Template:Link</ref><ref group="note">While some sources imply that this version was released on May 20, due to timezones differences it was actually released at 22:36 UTC on May 19 (which is 00:36 on May 20, Sweden time).</ref> which adds Minecraft:bedrock, Minecraft:water and Minecraft:lava, along with a Minecraft:world boundary and a new world generator.

Additions

Unobtainable to the player.
Bedrock and the layer above (if at the bottom of the world) is always dark even if exposed to the sky.
Generates at the bottom of the world and in world boundary.
Can't be broken, placed against, or otherwise selected.
Also called “unbreakable stone”.

A type of liquid.
Is transparent.
Spreads infinitely.
Doesn't work outside the map (it doesn't spread from world border after terrain generation).<ref>Template:Link</ref>
Saplings decay if placed in water.
Water spreads by duplicating itself to open horizontal and downward squares.

Pressing Template:Key cycles between four levels of render distance which was known as "Fog setting".<ref name="TigSource">Template:Cite</ref>
Pressing Template:Key generates a new level, with a new level generation screen.<ref name="TigSource"/>

No longer get reset on level reset, meaning there is no way to get rid of mobs now.<ref>Template:Link</ref>

General

An infinite ocean now surrounds the map, making it impossible to fall off the world.
The player can no longer pass the edge of the map.
Terrain is messier with more bumps visible on the surface. It also now generates in islands.
- The terrain always generates one block above ocean level.
- Lakes occur when the surrounding water is at a higher level than the terrain.
- All Minecraft:dirt with access to sunlight doesn't become grass blocks upon world generation if below water level.
Minecraft:Lava lakes also spawn occasionally.
Worlds made before this version receive a bedrock layer at the bottom of the map and an Minecraft:ocean surrounding it.

1 bug reported

The block being used to build does not show up unless it is a sapling.<ref>Template:Citation</ref>

The video released by Notch on May 18th showing off 0.0.12a is actually a developer variant that was never released to the public. See Development for more information on this.
To make the water and lava texture display slightly shorter than a block, its texture from Minecraft:terrain.png gets shifted down a bit in-game. This causes the texture to overlap with the block below at some angles.
The 0.0.13a-launcher jar contains the level generation files for this same version, which is also the same terrain generation files used in the full, public release of it (and 0.0.12a_01-03). It has variables that can enable and disable the uniform dirt layer, and it has been disabled for the public variant of 0.0.12a (or at least 0.0.12a_03 for certain). It also has variables for the water filling up the world from the corners, which can be disabled.