Minecraft Wiki
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Release date

October 4, 2012[1]

Snapshot for




12w40a is the tenth snapshot released for 1.4.2.


  • Added Swamp Hut structures, for Witches to spawn in.
  • Added superflat preset "Redstone Ready" with 52 layers of sandstone, 3 layers of stone, and 1 layer of bedrock.
  • Custom Item naming NBT tags (intended for custom map makers).
    • Using the NBT, it is possible to add custom names to items, as well as a lore list for that item.


  • Flatworld configuration now allows you to generate trees, strongholds etc.
    • Now pumpkins, tall grass, flowers, trees, mineshafts, dungeons, strongholds, lakes, desert wells, ravines and ores will spawn on superflat maps
  • Better inventory management
    • The pick block action now works on blocks that are represented as items in the inventory. (E.g.: Repeaters, redstone dust, tripwire)
    • Pressing the 1-9 hotkeys while hovering over an item will put that item into the inventory bar.
    • In creative mode, you can now shift-click items from the hotbar to the survival inventory screen
  • The left-click action will no longer open doors, pull levers, push buttons or open trapdoors. Use the right mouse button!
  • Firespread has been slightly nerfed again to prevent infinitely spreading fires
  • Beacon Texture altered, as well as the beam.
  • Eye of Ender can now be used in superflat worlds. (only if stronghold generation is enabled)
  • Slimes now spawn in Swamp biomes at low light level.


13 bugs fixed

  • Fixed the wither's starting explosion not being disabled by the mobGriefing gamerule[2]
  • Fixed a few crash bugs related to world generation, map item expansion, and other things.
  • Reverted previous lighting changes, which corrected such bugs as:
    • The Nether being extremely CPU intensive.
    • Map generation taking extremely long.
  • Fixed mob AI considering cobblestone walls as blocks of normal height.
  • Fixed a few texture oddities with the witch.
  • Fixed entities in water producing glitchy water sound.
  • Gaining multiple levels at a time will no longer play the leveling up sound over itself as many times as leveled.
  • Fixed the "A 64 bit Java installation is recommended for 'Far' render distance (you have 32 bit)" message being covered by the bottom 2 buttons.
  • Fixed pets teleporting around randomly[3]
  • Fixed being unable to place paintings larger than 1x2 and them popping off if they have been placed before
  • Fixed destroying blocks under you with Efficiency-enchanted gear
  • Fixed potion spawners crashing the game[4]