Java Edition Beta

Beta is the current development phase in Minecraft. It was announced on Notch's blog on December 11, 2010 and released nine days later, on December 20, 2010. As well as some minor updates, the transition from Alpha saw a 50% price increase (therefore making the cost 25% off the full price), a change in the disclaimer (Notch removed the line that said "all future updates will be provided free of charge", though the statement still applies to users who bought Minecraft before Beta was released. Although beta purchasers will get the full game but it is not guaranteed) and minor updates to the main website.

Features
Some of the major changes in the beta release that tops the Alpha releases include:
 * New Minecraft logo and launcher.
 * Achievements and Statistics.
 * Server-side inventory.
 * Weather.
 * Smooth Lighting effects.
 * New mobs including squids, Enderman, Silverfish, Cave Spider and tameable wolves.
 * New mechanics (Redstone Repeaters, Note Blocks, Power Rails, Detector Rails).
 * New blocks and recipes, such as Sandstone and the Lapis Lazuli Block.
 * Changed many of the older crafting recipes, like Ladders and Pressure Plates
 * Beds for skipping through the night and resetting spawn point.
 * More variety in trees.
 * Wool Dyes.
 * Charged creepers
 * Pigs get struck by lightning and become Zombie pigmen.
 * Maps
 * Trapdoors
 * Tall Grass in some biomes.
 * Pistons and Sticky Pistons
 * Shears
 * Naturally generated structures such as Strongholds and Abandoned Mine Shafts
 * NPC Villages
 * Ability to grow Melons and Pumpkins on farmland
 * New food items like Raw Beef and Raw Chicken, which can be cooked like Porkchops
 * Zombies drop Rotten Flesh instead of Feathers
 * A new hunger bar, which affects healing, and a new eating animation
 * Rewritten Biome and lighting code
 * Creative Mode, complete with the ability to fly and an infinite item selection menu
 * Iron Bars and Glass Panes
 * A full multiplayer server menu
 * Critical hits, charged bows, Experience Orbs, Sprinting, Blocking
 * New graphical effects, including improved sunrise/sunset, water bubbles, explosions, and Void particles
 * Animated Chests and Fence Gates
 * Vines and Giant Mushrooms which can be grown from regular mushrooms using Bonemeal

For full changes, see Beta version history.