Java Edition 1.2.1

1.2.1 is a major update to Minecraft released on March 1, 2012, which added a new height limit of 256 blocks (from 128) as a result of the Anvil file format, zombie sieges and generated features including jungle biomes, wooden bridges in mineshafts, and desert wells. It also added new blocks and items – bottles o' enchanting, redstone lamps, fire charges and chiseled stone bricks – and two new mobs, iron golems and ocelots.

Blocks

 * Chiseled Stone Bricks
 * Only available in creative mode.


 * Redstone Lamp
 * Crafted with glowstone and redstone.
 * Gives off light at a light level of 15 only when it is powered.


 * Jungle Log
 * New type of wood that spawns as jungle tree trunks.
 * Has a slightly mossy brown texture with horizontal bark.


 * Jungle Leaves
 * Generates in jungle trees and as bushes in jungles.


 * Jungle Sapling
 * Can be grown into jungle trees and drops from jungle leaves.


 * SandstoneGlyphs-Unused.pngSandstoneFace-Unused.png New textures
 * Not available in-game and have no block equivalents.
 * Planned to be used as decorative sandstone variants.

Items

 * Bottle o' Enchanting
 * Can be used to spawn experience orbs.
 * Only available in creative mode.


 * Fire Charge
 * Produces fire when.
 * Can be fired out from dispensers.

Mobs

 * Iron Golem
 * Occasionally spawns in villages.
 * Attack zombies and other hostile mobs.
 * Can be spawned by placing 4 iron blocks and pumpkins in a specific pattern.


 * Ocelot
 * Can be tamed using raw fish.
 * Tamed ocelots will scare off creepers and teleport to the player similarly to tamed wolves.

World generation

 * Jungle biome
 * A very dense, uncommon biome featuring large jungle trees that can reach up to 31 blocks tall with 2×2 thick trunks. Oak trees can also be found. Jungle leaves cover much of the forest floor.


 * Desert wells
 * Rarely found in deserts.
 * Are comprised of sandstone with a single water source in the middle.


 * Mineshafts
 * Generated with wooden bridges in midair portions.

Gameplay

 * Zombie sieges
 * Comprised of a large number of zombies.
 * Spawn occasionally at night in villages.

General

 * World file format
 * Added the Anvil file format, replacing MCRegion.
 * Height limit increased from 128 blocks to 256 blocks.
 * A total of 4096 block IDs can be used.
 * Old worlds will alert the message, Must be converted!
 * World selection screen shows worlds saved in Region file format, and will convert them.
 * No longer shows worlds saved in Alpha level format.

Blocks

 * Dispenser
 * Changed texture.


 * Grass
 * Placing blocks on grass will now replace the grass.


 * Ladders
 * Re-added collision box.
 * Crafting recipe now yields 3 ladders instead of 2.


 * Lava
 * Lava now has a faint rumbling sound effect, and large particles that hop out of the lava produce a popping sound.


 * Oak Sapling
 * Changed texture.


 * Slabs and stairs
 * Can be placed upside-down by placing them below a block.
 * Crafting recipe for slabs now yields 6 instead of 3.


 * Vines
 * Can now be climbed like ladders.

Mobs

 * Cave spider
 * Now swim quickly.


 * Creepers
 * No longer strafe to the player's left but now simply stop in front of the player when they are about to explode.


 * Villager
 * Will now breed if there are enough empty houses in a village.


 * Wolf
 * Tamed wolves can be bred using bones.


 * Zombies
 * Can break down doors on Hard difficulty and in Hardcore mode.
 * Now have a rare chance to drop an iron ingot, iron helmet, iron shovel, or iron sword.
 * Will now navigate to the nearest shadow or body of water for safety when they catch fire.
 * Will chase and attack villagers.
 * Sometimes zombies will prioritize attacking villagers instead of the player, and will always chose the shortest way to the target, even if there was a door in the way.


 * Skeletons
 * Now have a rare chance to drop a bow or an enchanted bow.
 * Will now navigate to the nearest shadow or body of water for safety when they catch fire.


 * Snow golems
 * Will now melt and die in the Nether.


 * Zombie pigmen
 * Now have a rare chance to drop a golden helmet, gold ingot, or golden sword (which may be enchanted).
 * Now swim faster in water.

Gameplay

 * Debug screen
 * Added items:
 * lc: Largest section height
 * b: Current biome
 * bl: Block brightness
 * sl: Sky brightness
 * rl: Raw brightness


 * Multiplayer
 * Now that biome data saves to chunks, multiplayer servers no longer send clients the world seed, instead the seed will display as "0" to the client.


 * Third person view
 * Now has a slight delay on the speed at which the head moves on the player.
 * Makes it possible to see the sides of the player's head.

Fixes

 * 3 bugs fixed
 * Doors have been updated so that double doors work better with redstone.
 * Ambience now works in multiplayer.
 * Mob spawners show the correct mob in multiplayer (instead of a pig).

Video
Similar to Java Edition 1.1, an official video documenting some of the 1.2's major features was released on Mojang's official YouTube channel on March 1, 2012. The video was made by Hat Films, who have made update trailers and videos for Mojang in the past.

Trivia

 * Development versions for 1.2 started only a week after 1.1 was released.