Java Edition 15w49a

15w49a is the forty-fourth snapshot released for 1.9.

Additions

 * Sound events
 * (Removed in 15w49b)
 * (Removed in 15w49b)
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * (Removed in 15w49b)
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * Statistics
 * : Tracks the distance a player has glided using elytra.
 * : Tracks the distance a player has glided using elytra.

Blocks

 * Beacon
 * Now drops any contained item when exiting the GUI.
 * No longer accepts items from hoppers.
 * NBT tag removed.
 * Cactus
 * Will break if lava is adjacent.
 * Cactus on sand will break if water or lava is in the block above.
 * Cobweb
 * Cobwebs now catch snowballs, eggs, thrown potions, XP bottles, and ender pearls, causing the item form of the projectile to be dropped. (Removed in 15w49b)
 * Crops and nether wart
 * Hitbox now changes as the plant grows.
 * Doors
 * Are now placed facing left/right depending on which half of the block you click on, unless neighboring doors cause them to place a certain way.
 * Elytra
 * Increased damage when flying into a wall.
 * End crystals
 * Now require air or replaceable blocks in the two blocks above the block it's being placed on.
 * Can no longer be placed to intersect other entities.
 * Fire
 * Chance of going out in rain increased by 20 percentage points (now 20% + 3 percentage points per age).
 * Furnace
 * The  block is no longer available as an item.
 * Lily pad
 * Bounding box changed, now 15/256 high (from 1/16) and inset from three edges of the block by 1/16.
 * Melons
 * Melons and glistering melons are now oriented the same way. (Removed in 15w49b)
 * Pistons
 * Unextended pistons, downwards-facing pistons, and upwards-facing piston extensions are now considered to have a solid top surface, like upside-down stairs and top-half slabs.
 * Among other things, this means mobs can now spawn on them.
 * Powered rails and activator rails
 * Powered rails and activator rails no longer transmit power to each other.
 * Tripwire and tripwire hooks
 * Removed the distinction between "suspended" and "non-suspended": formerly, tripwire would only work if the whole stretch and both hooks were all above solid blocks or all not above solid blocks.
 * Trapped Chest
 * Now appears in the Redstone tab of the Creative inventory instead of Decoration Blocks.

Mobs

 * All mobs
 * Improved path finding
 * Zombies, Zombie Pigmen, Slimes, Magma Cubes, Wither Skeletons, Spiders, Cave Spiders, Silverfish, and Endermites now fight back when hit by other mobs.
 * Knockback no longer changes the Y-axis speed of flying and falling mobs.
 * Ender dragon
 * No longer teleports through Nether portals or End portals.
 * Can no longer ride anything.
 * Can no longer have status effects.
 * Enderman
 * Can no longer pick blocks from behind walls.
 * Horse
 * Now rotates with the player.
 * Shulker
 * No longer float above the ground.
 * Skeleton
 * No longer find shade to hide under if equipped with a helmet.
 * Snow golem
 * Using shears on a snow golem will remove the pumpkin head (and remove 1 durability from the shears). The pumpkin is not dropped.
 * Wither
 * No longer teleports through Nether portals or End portals.

Non-mob entities

 * Arrow entity
 * Now take the thrower's motion into account. For example, an arrow fired forward by a player in a speeding minecart will fly faster relative to the ground, an arrow fired backwards will fly slower, and an arrow fired sideways will have motion in the direction of minecart travel.
 * Arrows that bounce off a target (e.g. a shield or a sitting dragon) and may be retrieved will become dropped items if near zero momentum after being bounced.
 * SmallFireball entity
 * No longer damages (or angers) fire-immune entities.
 * Thrown projectiles (snowballs, eggs, ender pearls, bottles o' enchanting, and thrown potions)
 * No longer collide with non-opaque blocks.
 * Even non-opaque blocks that are solid, such as glass. See.
 * Are "caught" and converted to the item form by cobwebs.
 * Now take the thrower's motion into account. For example, an arrow fired forward by a player in a speeding minecart will fly faster relative to the ground, an arrow fired backwards will fly slower, and an arrow fired sideways will have motion in the direction of minecart travel.

Command format

 * now auto-completes itself when pressing TAB.
 * now has an optional  parameter to specify which players can see the particle when inside the range. When left out, everyone in range can see the particles. Also added a   parameter to specify particle parameters (for iconcrack_, …).

General

 * Combat
 * Sweep attacks now do damage to mobs affected by the knockback.
 * The Infinity enchantment no longer affects Spectral and Tipped arrows.
 * End portal
 * In the 0.0000000001% chance that all 12 frame blocks generate with eyes already present, the portal will now be active.
 * This means once again you can access the End without going to the Nether.
 * Exhaustion
 * Sneaking now increases exhaustion by half as much as walking.
 * Frost Walker enchantment
 * Now functions whenever the player is standing on ground, regardless of whether the ground is a solid block or not.
 * No longer works on armor stands.
 * Lightning
 * No longer destroys item frames, leash knots, paintings, and armor stands.
 * Sounds
 * Renamed sound event  to.
 * Status effects
 * Health Boost effect now shows multiple red hearts instead of the one similar to Regeneration.
 * Absorption effect now shows a single red heart with a yellow outline around it.
 * Nausea effect will now stop instantly when cleared using Milk or with commands.

Video
Video made by slicedlime: