Java Edition 15w31a

15w31a is the first snapshot released for 1.9, and the first snapshot released in 2015 (not counting 15w14a, which is an April Fool's hoax snapshot).

Blocks

 * Chorus flower
 * Spawn on the top of the chorus trees.
 * Breaks if the supporting block below is broken.
 * It only drops when mined directly.
 * Can only be planted on end stone in any dimension.
 * It will show a different texture when it stops growing.
 * Chorus plant
 * Generate in the End.
 * Can be grown using chorus flowers.
 * Breaks in quick succession if the supporting chorus plant below is broken.
 * Drops chorus fruit.
 * Dragon head
 * While a player wears the head and moves, the head's mouth opens and closes repeatedly.
 * When powered with redstone while it's placed on solid block, the jaw starts to open and close.
 * It will keep the mouth position of the exact moment it was unpowered.
 * End Gateway
 * A portal block used to transport the player to the new outer regions of the end.
 * The texture is identical to the end portal block, but the model is that of a full block rather than plane.
 * The player cannot use or  to obtain it.
 * It can only be set by using.
 * Naturally generates after killing the dragon and traveling someplace new in the End with it.
 * Shows yellow beacon beam when created and used.
 * End rod
 * Generates in the End city dungeons.
 * Placeable horizontally and vertically.
 * The model has a little base that is oriented against the block it was placed on.
 * If it's placed on top of another rod, then it will have the opposite orientation.
 * Produces white particles.
 * Used as a lighting source with the same efficacy as torches.
 * Unlike torches, they are tangible.
 * Horizontal end rods can be stepped up onto like slabs.
 * End stone brick
 * Generates in the End city dungeons.
 * Can be crafted with 4 blocks of end stone.
 * Grass path
 * Are visually 15/16 block high
 * Obtainable by right-clicking grass with a shovel.
 * Drains the shovel's durability.
 * Drops dirt, even when using silk touch.
 * Cannot be obtained in the creative inventory.
 * But unlike farmland, it can be obtained by using the key in creative.
 * Purpur block
 * Generates in the End city dungeons.
 * Can be crafted with popped chorus fruit.
 * Purpur pillar
 * Generates in the End city dungeons.
 * Can be crafted with purpur slabs.
 * Purpur stairs
 * Generates in the End city dungeons.
 * Can be crafted with purpur blocks.
 * Purpur slab
 * Generates in the End city dungeons.
 * Can be crafted with purpur blocks.
 * Structure block
 * Only placable via.
 * Can be used with NBT tag parameters ( or )
 * GUI is only used by Mojang employees
 * Has a letter on the texture based on its mode.

Items

 * Arrows
 * New spectral arrow:
 * The tip is gold colored, but just in the item model.
 * Shows mob and player outlines in their respective team color when hit – even when invisible.
 * NBT tag for entities to disable outlines. [Tag?] (please add corresponding tag here)
 * NBT tag to force outline:.
 * The glowing is a status effect.
 * Crafted by surrounding an arrow with 4 glowstone dust.
 * Yields 2 spectral arrows.
 * Arrows can be tipped with potions.
 * 14 new arrow types in total.
 * Each differently tipped arrow is available in the creative menu, just like enchanted books.
 * Corresponding effect is applied on hit.
 * Beetroot
 * Restores.
 * Spawns naturally in villages.
 * Can be used to craft beetroot soup.
 * Can also be used to craft rose red dye.
 * Beetroot soup
 * Restores.
 * Crafted from 6 beetroots and a bowl.
 * Beetroot seeds
 * Used to grow beetroots.
 * Chorus fruit
 * Obtained from chorus plants.
 * Can be eaten even if the player is not hungry, similar to golden apples.
 * Teleports the player to a random nearby location when eaten (like an enderman or shulker).
 * Does not heal hunger points if the hunger bar is full.
 * Otherwise it will heal.
 * Can be cooked in the furnace to obtain Popped Chorus Fruits.
 * Popped chorus fruit
 * Obtained from cooking chorus fruit.
 * Used to craft purpur blocks.
 * Cannot be eaten.
 * Shulker spawn egg
 * Used to spawn a shulker.
 * Purple with darker purple spots.

Mobs

 * Mobs have a 5% chance to spawn left-handed, through the new  boolean tag.
 * Mobs able to hold items, will hold them according to their dominant hand.
 * Shulker
 * Short for "Shell Lurker".
 * A hostile mob with the appearance of a purple block.
 * Only spawns on the ground or at the walls of end cities when they first generate.
 * When attacking, it opens its shell on a spinning animation, revealing the creature inhabiting.
 * The creature looks a like a little white cube with big eyes.
 * Its attack consists in shooting projectiles.
 * The projectiles chase the player until it's out of range.
 * They can only move along one of the three grid axes at a time and on integer steps.
 * This means they can only move through taxicab geometry.
 * Projectiles can be knocked away by attacking them.
 * Getting hit by a projectile causes 2 hearts of damage and inflicts the levitation status effect.
 * They take more damage while their shell is open.
 * It has an idle animation, where it opens its shells a little to peak through.
 * It can be pushed by pistons, and resists being placed on any position that isn't 3 integers (except if they are on minecarts).
 * It can teleport like an enderman.
 * It sometimes does this while being attacked or placed in unusual circumstances:
 * Removing its support block.
 * Pushing it into a non-air block (except piston heads).
 * Pushing a non-air block into its position (except piston heads).
 * It's one of the few entities (apart from boats and minecarts) that can be stood upon.
 * It even displaces the player properly during its attacking and idle animations.

World generation

 * End City
 * Generates on the new outer end islands.
 * Dungeon-type structure fashioned like a branching tower made of endstone and many of the new blocks.
 * Resembles a tree house.
 * Generates with shulkers in it.
 * End ship
 * It sometimes generates up in the air, right next to the end city dungeon.
 * It always generates sailing away from what appears to be a pier.
 * Composed of many of the same materials as the end city.
 * Generates with shulkers in it.
 * Has a speed beacon, a brewing stand with potions of healing, and other various loot.
 * Chorus trees
 * Tree-like arrangements of the new chorus plant and chorus flower blocks.
 * Generate on the outer end islands
 * The whole structure is destroyed when the bottom-most block is destroyed, like cacti.
 * Can be farmed by planting the chorus fruit flowers that come from the top of the plants.
 * Unlike cacti, chorus plants do not require the supporting block to be below it, but rather adjacent.
 * This allows the structure to grow around obstacles, like other plants.
 * End Gateway Portal
 * A small structure consisting of an end gateway block and two little bulbs of bedrock, at both the bottom and the top.
 * It is an alternative way of traveling to the outer end islands, without having to build or fly all the way over there.
 * Since the bulbs of bedrock only leave a one block slit on the horizontal plane, it is only accessible by throwing ender pearls at it, or by riding pigs, boats or minecarts.
 * The player will be teleported to somewhere on the outer end islands.
 * The final location of the player depends on what angle they entered or at what angle the enderpearl was thrown at.
 * One gateway is created for each dragon kill.
 * Up to 20 are possible this way.
 * Gateways spawn in a radius around the end portal.
 * Another gateway is created everytime the player teleports to a new location.
 * the created gateway is linked to the original so the player has a way back.

Gameplay

 * Dominant hand option
 * An option for players to change their dominant hand on their player model.
 * Under "Skin Customization".
 * Changes the orientation of the offhand slot in the hotbar (left often suits right-hand players better and vice versa).
 * Dual wielding
 * Players can now use both hands at the same time to do different actions, with the left and right mouse buttons.
 * For example, if a player has a pickaxe in his/her main hand and a torch in their other hand, right clicking will place the torch.
 * This happens because a pickaxe lacks a right click use, and therefore the game tries to then treat the other item as if it's being right clicked.
 * The player cannot click both buttons at the same time.
 * This is achieved through an extra inventory slot called the "offhand" slot.
 * Pressing (by default) will switch whatever item is selected in the hotbar with the item in the offhand (including no item).
 * The offhand slot is displayed next to the hotbar when it's not empty (left for right-hand players and vice versa).
 * It's also available in the inventory screen.
 * Only the main hand can be used for attacking.
 * Even bows can't be used in the offhand.
 * Bows can be used when something else is in the offhand.
 * Arrows in the offhand take priority over arrows in the rest of the inventory slots.
 * The offhand model is invisible in first person view, while it's empty.
 * Some attributes and enchantments will apply to the offhand item, while others will not.
 * Status effects
 * Received when the player is hit by shulker projectiles.
 * Makes player involuntarily float high into the air.
 * Can be used to get to higher places.
 * Listed as a negative effect, due to the potential to kill from fall damage.
 * Higher levels of levitation result in faster floating, except for the last two:
 * Effect level 255 does nothing.
 * Effect level 254 results in slow fall (similar to lunar gravity).
 * Received when players or mobs are hit by spectral arrows.
 * Makes player's outline glow, seen even through non-transparent blocks.
 * The outline includes the models of the currently held items.
 * Listed as a negative effect, because it prevents players from hiding from other players.
 * It becomes colored differently if the player is part of a team, to match its team color.
 * Listed as a negative effect, because it prevents players from hiding from other players.
 * It becomes colored differently if the player is part of a team, to match its team color.

Command format

 * NBT tags
 * Added tags,  ,  , and   to.
 * Added tags  and   to.
 * Added tag  to.
 * Added tag  to.
 * Added tag  to
 * Added entity, child of.
 * Added entity, child of.
 * Added entity, which extends   and has no unique tags.
 * Added entities  and , children of.
 * Added block, child of.
 * Added block, child of.
 * Added item tag, child of.

Blocks

 * Dead bushes
 * Will now drop anywhere between 0–2 sticks when broken without shears.
 * Fire
 * The block states flip and alt were removed, and the integer state upper was reimplemented as the byte state up.
 * This reduced the number of states representing fire from 3072 to 512.
 * Trapdoors
 * No longer require supporting blocks.
 * Therefore they can be moved by pistons freely.
 * An open trapdoor may be climbed like a ladder if it is directly above one and on the same side of the block.
 * Stairs
 * Are now rotated 90° in the inventory.
 * Pressure Plates
 * Have now a slightly thinner item model.
 * Glass panes & Iron bars
 * Glass panes/iron bars without any connecting blocks are now 2x2 pixels in footprint.
 * This is compared to the big cross configuration that was the default.
 * Doors
 * Changed the shading on acacia, birch, dark oak and jungle doors.

Items

 * Bows
 * The bow in the hotbar now shows an animation for drawing back an arrow.
 * Arrows in the off hand are prioritized over arrows in the rest of the inventory slots.
 * Chests
 * Unlike other blocks: chests, trapped chests and ender chests have their item model rotated, to have the front face in view of the player.
 * This made it easier to distinguish between trapped and regular chests while being held, since only their front face is different.
 * Ender pearls
 * Can now be thrown in creative mode.
 * Maps
 * Now display as a mini map when held in the off hand, or if the offhand slot is occupied.
 * The (old) large version is visible only when held in the dominant hand with both hands free.
 * Fishing rods
 * Casting fishing rods now has an animation in the hotbar/inventory.
 * Potions
 * Mixed potions' colors now blend.
 * Numeric IDs are no longer used. Instead an NBT "Potion" tag is used.
 * e.g.
 * Splash potions now have a separate data value and ID name and can be created from all potions, including water bottles.
 * Added Mundane, Thick and Awkward potions to the creative inventory.
 * Glowstone dust or redstone can no longer be added to extended or tier-II potions respectively.
 * Most recipes for potion of Weakness were removed; only brewing from a water bottle remains.
 * Potion of Slowness can no longer be brewed from a potion of Fire Resistance.
 * Potion of Harming             can no longer be brewed from a potion of Water Breathing.

Mobs

 * Ender dragon
 * Similar to the one on console edition.
 * The dragon can be re-spawned indefinitely by creating a creeper face configuration out of clay in the End.
 * Subsequent dragons will spawn new gateways, but won't drop XP or create new dragon eggs.
 * The dragon AI and attacks has been changed:
 * Breathes fire/purple particles on players and mobs, while on top of the portal.
 * Drops fireballs on top of the player.
 * Defends the obsidian pillars more, the further the fight progresses.
 * The dragon flies and stops over the portal sometimes, only then can the last blow be dealt.
 * Villagers
 * Farmer villagers now harvest beetroot.
 * Skeletons
 * Have an animation for lifting up and drawing back their bow.
 * Endermen
 * Remain aggravated towards the player despite being in contact with water.
 * Drop the block they were holding when killed.
 * Pigs
 * Can be led and bred with potatoes and beetroots, in addition to carrots.
 * Chickens
 * Can be led and bred with melon seeds, pumpkin seeds, and beetroot seeds, in addition to regular seeds.

Non-mob entities

 * Projectiles
 * Slightly altered the path of projectiles.
 * Armor stands
 * Can now be summoned to dual wield with commands in creative.

World generation

 * The End
 * A set amount of differently-sized obsidian pillars are arranged in a circular fashion.
 * The tallest pillars have iron bars around their ender crystal to deflect projectiles.
 * The exit portal is pre-generated at the center of the island, but without the dragon egg and portal blocks.
 * Now generates an great amount of islands in every direction from the main island, though separated from it in all directions by an empty gap of about 1,000 blocks.
 * Mini islands generate between the center and main islands.
 * End islands and mini end islands have chorus trees spread throughout them.
 * The Nether
 * Removed the Nether fog.
 * Villages
 * Farms now include beetroot crops.

Gameplay

 * Inventory
 * Rearranged the survival inventory and the creative "survival tab" to accommodate for the new offhand slot.
 * Unified the orientation of many items in the inventory.
 * Status effects
 * Status effects icons are now displayed on the HUD on the right hand corner, instead of just in the inventory (similar to Pocket Edition).
 * They are ordered by the time of infliction from right to left.
 * Positive effects are on the top row and negative effects on the bottom row.
 * Effects that are about to run out, blink.
 * They blink faster when they are closer to running out and start fading away.
 * Crosshair
 * No longer shows the crosshair in 3rd person view.

Command format

 * NBT tags
 * Tag  (under  ) has become deprecated.
 * Tag  (under  ) has become deprecated.

General

 * Options
 * Removed the Broadcast Settings section, as well as Twitch integration as a whole.
 * Removed Super Secret Settings and Alternate Blocks from video settings.
 * Attributes
 * will make the name tag on mobs show in the same way as on players.
 * Entities can now be summoned straight to teams:.
 * and  tags are no longer used.
 * ,,   and   are used instead.
 * Bosses
 * Proper support for multiple bosses’ health bars, so they show at the same time without obstructing each other.
 * Damage tooltips
 * Items can damage differently based on where they are placed to (main hand, offhand, armor slots).
 * Death messages
 * Death messages will now be displayed on the player's death screen as well as in the chat.
 * Models
 * Different models/textures can be used for each different damage values, item states, and whether the item is held in a different hand.
 * This works on compasses, clocks, and anything that can have a durability bar.
 * It also contains additional tags for bows and fishing rods.
 * Models can be put together based on block state attributes, such as fences.
 * As a result, the vanilla set of block models was reduced by almost 300.
 * Block model JSON is now strict: comments and quote-less identifiers are not allowed.
 * tag defaults have changed, and the  and   tags were replaced with ,  ,  , and.
 * and  tags can coexist now, though the top level elements tag overwrites all former ones.
 * UV is now optional, and if not supplied it will automatically generate based on the element's position.
 * Resource packs
 * The required pack version number was changed to "2" in.
 * Older resource packs require user acknowledgment to use.
 * Structure data
 * Now comes from.

Video
Video made by slicedlime:

Trivia

 * 15w31a holds the record as having the most content in one developmental release, having nearly twice as much content as 1.4.2 had in October 2012.
 * The previous record was held by 13w36a for 1.7.2.