Java Edition 16w20a

16w20a is the first snapshot released for 1.10.

General

 * Sound events


 * Options
 * A new 'Auto-jump' button which automatically moves the player onto a position one block higher when against a raised block (instead of using the spacebar).
 * The option is turned on by default.


 * Loot tables
 * A new tag  for the   function.
 * Limits an amount to the specified value if it goes over it. (for example in stray.json (loot table), the amount of tipped_arrows that will be dropped are always limited to max 1 even with a level III looting sword.)


 * Particles
 * A new 'fallingdust' particle, that falls from the bottom of gravel, sand, red sand and anvils (not dragon eggs), when they are floating in the air.


 * NBT tags
 * 0: default, 1-5: villager, 6: husk.
 * Replaces IsVillager and VillagerProfession, they still function, but are no longer saved in the entity.
 * Replaces IsVillager and VillagerProfession, they still function, but are no longer saved in the entity.


 * Debug screen
 * + shows the chunk borders around the player

World generation

 * Fossils
 * Generates 15–24 blocks underground in Desert, DesertHills, Desert M, Swampland, and Swampland M biomes. Each chunk has a $1/64$ chance of generating a fossil.
 * Composed of bone blocks and some coal ore.
 * The .nbt files can be found in the structures folder within the 16w20a jar and can only be loaded using the structure block when you put the files into the world folder.
 * The easiest way is to save a new structure using a special name, and search on your machine for that name. Put the structures in the same folder to load them. (Worth noting, on Mac OSX, this folder may be in the wrong location since the structures are saved under ".minecraft/User/.../worldname/structures/..."
 * There are 4 variants of the skull, and 4 variants of the spine sections.

Blocks

 * Structure void
 * Used for the structure block to keep the blocks in that location (formerly barrier blocks were used by the devs, which means you can now use barrier blocks in structures.)
 * Are invisible, have a small hitbox and are only visible when using the feature in (save) structure blocks.
 * Are invisible, have a small hitbox and are only visible when using the feature in (save) structure blocks.


 * Magma block
 * Found in the Nether, generating 4 veins per chunk between Y=27 and Y=36, similar in size to underground dirt, gravel, andesite, and such in the Overworld.
 * Crafted using four magma cream.
 * Mobs take half a heart of damage every second while touching it, similar to a cactus.
 * If a mob is crouching, wearing Frost Walker-enchanted armor, or under the Fire Resistance effect, it does not take damage.
 * Death message: "[Player] discovered that floor was lava."
 * Death message after being damaged by mob: "[Player] walked into danger zone due to [Mob or Player]."
 * Removes water blocks on top when randomly ticked.
 * Preserves block light sources
 * For example, a magma block next to a torch will emit light at level 13, as that was the light level it received from the torch.


 * Nether wart block
 * Crafted by filling a 3x3 square in the crafting table with nether wart.


 * Red nether brick
 * Crafted by placing a 2x2 checkerboard of 2 nether brick and 2 nether wart in a crafting table.


 * Bone block
 * Crafted by filling a 3x3 square in the crafting table with Bone Meal.
 * Placing it in a crafting table yields 9 bone meal back.
 * Found underground in desert and swamps. They look like fossils.

Items

 * Spawn eggs
 * Now exists for:
 * Wither skeleton
 * Mule
 * Skeleton horse
 * Zombie horse
 * Donkey
 * Cat
 * Elder guardian
 * Polar bear
 * Stray
 * Husk

Mobs

 * Polar bear
 * Adults and children spawn randomly as passive mobs in Ice Plains, Ice Mountains, and Ice Plains Spikes.
 * When hit, the adults will attack you, the cubs will run away (very fast, similar to baby zombies).
 * Additionally, adults will always attack you when their cubs are around
 * Adults can swim faster in water than the player.
 * Drops 0–2 raw fish (75% chance) or 0–2 salmon (25% chance), each increased by 1 per level of Looting.


 * Stray
 * Acts mostly like a normal skeleton.
 * Drops are the same as skeletons, but also have a 50% chance to drop 0–1 tipped arrows of Slowness when killed by the player. With Looting, chance increases to $2×level+1/2×level+2$.
 * Is a skeleton with the SkeletonType dataTag set to 2.
 * Spawns in cold biome types (e.g. Ice Spike Plains).
 * Spiders spawned in cold biomes have a chance of having a stray riding it.
 * Shoots Tipped Arrows of Slowness (0:30) at the target.
 * You can ricochet the Tipped Arrow on the Stray to inflict itself with its own effect.


 * Husk
 * Behaves mostly like a zombie (it has the ZombieType dataTag set to 6)
 * Does not burn in sunlight.
 * Is a Zombie with the ZombieType dataTag set to 6.
 * Spawns in warm biome types (e.g. Deserts).
 * Can spawn as a baby or as a chicken jockey.
 * Applies 6 seconds of hunger when attacking in Easy, 13 in Normal and 20 in Hard difficulty
 * 2 pixels taller than zombies

General

 * NBT tags
 * Now exists for all entities, not only armor stands.
 * Now exists for all entities, not only armor stands.


 * F3 Debug screen
 * The 3D graph replacing the standard crosshair now has a black outline.
 * Fixed in next snapshot (https://bugs.mojang.com/browse/MC-102091)


 * Huge mushrooms
 * Huge mushrooms have a $1/12$ chance of generating twice as tall as normal.

World generation

 * Plains and Sunflower Plains
 * Now have some trees (5% of chunks). $1/3$ large oaks, $2/3$ normal oaks.


 * Ice Plains, Ice Mountains, and Ice Plains Spikes
 * Have a lower chance of spawning passive mobs during world generation than other biomes (7% versus 10%).


 * Mesas, including all variants
 * Hardened clay and stained clay no longer generate more than 15 blocks deep, if the mesa is more than 15 blocks above sea level.
 * In addition to the normal 2 veins of gold ore below Y=32, attempts to generate 20 veins between Y=32 and Y=79.
 * Generate the new type of abandoned mineshafts, described below.


 * Abandoned mineshafts
 * New mineshaft type that generates in mesa biomes (including all variants).
 * Placed so that the midpoint of the structure is near sea level, rather than so that the top is 10 blocks or more below sea level.
 * Uses dark oak wood for wooden structures.
 * New NBT tag  on mineshaft structure pieces to indicate the type. 0 is the traditional mineshaft, 1 is the new mesa mineshaft.
 * Features generate differently if above ground (i.e. the sky light where they generate is 8 or more). This is not dependent on mineshaft type.
 * Cave spider spawners no longer generate if sky light is 8 or more.
 * Various wooden pieces no longer generate if the block above is air and/or if sky light is 8 or more.
 * Rails in corridors are more complete if sky light is below 8.


 * Villages
 * Now generate in Taigas (but not variants).
 * Village structures are no longer restricted by biome, meaning that a village that starts in a valid biome can now spread into an adjacent invalid biome.
 * Now generate with spruce wood in Taigas and acacia wood in Savannas.
 * In Savannas, acacia logs replace cobblestone in all structures except churches.
 * Paths no longer generate below sea level (meaning they will attempt to bridge ravines) and in non-desert villages have different material depending on the existing terrain.
 * If replacing grass blocks, the path is made from grass path blocks.
 * If replacing liquids, the path is made from planks.
 * Otherwise, the path is gravel on top of cobblestone.
 * Have a 2% chance of being a zombie village.
 * All generated villagers are instead zombie villagers. These have no special resistance to sunlight and may despawn.
 * There are no doors or torches in the village.


 * Caves
 * No longer turn sand in the ceiling into sandstone when generating.

Blocks

 * Structure block
 * New textures for each different mode.
 * Are now available in item form, can be given or summoned. (but only used in creative)
 * Now comes with a usable, easy GUI, in a way that's good for map makers
 * Structures can be stored, bundled and loaded per world, in the "structures" folder
 * Structures are size-limited to 32 blocks in each direction, coordinates are relative
 * A way for command blocks to place structures
 * 4 modes
 * D, data - for chest markers and other blocks that require data (default)
 * S, save - build structure in world, tell the block where it is and it saves it to file
 * L, load - loads saved structure files, replacing blocks with saved blocks except for barrier blocks
 * C, corner - for automatic size calculation
 * Shows outline of the structure it relates to in white
 * Can rotate/mirror blocks
 * L and S structure blocks can be activated by redstone
 * Only opped creative players can break or place them and save structures
 * Placing structures is "most likely faster than the /clone command in the majority of use cases"
 * Protection against maps saving arbitrary amounts of data to disk
 * Saving entities is not working properly yet, may only come at a later date
 * Red and blue small little cubes can be displayed in the selection area
 * Blue is for air blocks, red is for structure void blocks
 * Display a name tag above them indicating their mode and structure name
 * End stone bricks
 * Are no longer craftable.

Items

 * Firework rocket
 * Recipe now produces three rockets rather than only one.

Mobs

 * Endermen
 * Can now rarely spawn in the Nether. Spawn rate is $1/153$ (compared to $2/153$ for magma cubes, $100/153$ for zombie pigmen, and $50/153$ for ghasts).
 * Can now naturally pick up netherrack


 * Magma cubes
 * Spawn about twice as often in the general Nether (rate is now $2/153$, was $1/151$)

Fixes

 * More fixes:
 * Fixed some broken uses of relative coordinates