Java Edition Classic

POP was the second phase in the development cycle of Minecraft (Java Edition), following pre-classic and preceding Indev, and was the first Minecraft development stage to have some of its versions released to the public. This phase was commonly named "alpha" during its development until June 28, 2010, when a blog post was written to name the development phases of Minecraft. Creative and later Survival game modes were introduced in this phase.

The release of Survival mode in Classic was conducted in a series of tests named Survival Test. It was a very early version of the game mode. The test had a point-based system, where the player could acquire points from killing some of the game's first mobs. Even after Classic was phased out, Survival Test was still playable until the website received a major overhaul on December 16, 2010, where it was quietly removed.

Classic does not support many of the main features in the current versions such as crafting or a proper inventory. Indev through Beta 1.7 did not contain a "creative" mode, so players continued to use Classic for building things that would take too long in newer versions. The addition of Creative mode in Beta 1.8 rendered Classic obsolete.

History
Sand has been available for use since Classic. During that time, sand blocks were rare and only appeared naturally in one block-thick beaches (usually by water or in the middle of a landscape). These beaches were always level and below Ocean level. Sand instantly appeared at the lowest point it could go when placed above an air block without any sort of falling animation. Destroying a pillar made from sand from the bottom would cause the sand to disappear from the top first. Gravel and sand "fell" when placed in mid-air by moving directly above the nearest block directly below them, instead of turning into falling block entities and falling. These attributes were present until the release of Infdev.

An old glitch in 0.0.23a_01 allowed players to raise the height of a fluid block by placing sand (or gravel) over it. The sand block would stay suspended in mid-air until it was broken. When broken, a fluid block corresponding to the type below the gravel or Sand would appear where the block was. The suspended fluid block would remain immobile until a block was placed next to it, causing a flood. This bug has since been fixed, but has been reported that it has happened before.

An interesting and often humorous quirk in Classic is that whenever the player moves, they will swing their arms wildly around. This was changed in Indev and removed in Alpha v1.0.9.

Website availability
The latest version of the Classic Creative game mode had been still playable for free on Minecraft's website. It was no longer updated and only kept for historical purposes. According to Notch, he planned on "...slowly phasing it out. I won't remove it, though. Just hide it." It was playable in both singleplayer and multiplayer variations. There were mods which had been added to multiplayer, making the game more varied in gameplay. Some special custom game modes like Capture The Flag, Lava Survival, TNT Wars or Zombies had also been created.

On August 8, 2012, the link on the website to Classic was removed, but re-added after many complaints. On July 1, 2013, because of the new launcher being able to play Classic, the link to Classic was removed again, though the page remained playable. The Classic game at that page went unsupported for some time, meanwhile several major browsers increased their default Java security to the point where the game became essentially unplayable, until at some point between September 10 and 12 2015, the page containing Classic was itself removed entirely.

On May 7, 2019, a recreated Javascript version of Java Edition Classic 0.0.23a_01 was made available to play on the Minecraft website as part of the game’s tenth anniversary celebrations.

Early Classic Creative

 * Bedrock
 * Water
 * Lava
 * New world terrain, featuring hills and lakes
 * Sand
 * Gravel
 * Coal, iron, and gold ore
 * Trees, logs, and leaves
 * Spawn point saving and reloading
 * New textures for wood planks and cobblestone

Multiplayer Test

 * Multiplayer, players now take the same model as human mobs previously
 * Humans can no longer be spawned by pressing G
 * Commands
 * Animated water and lava
 * Sponge
 * Glass
 * Block of gold
 * Red and brown mushrooms
 * Dandelion (known as "yellow flower" at the time)
 * Poppy (known as "rose" at the time)
 * Wool (known as "cloth" at the time) in 16 colors, including white

Survival Test

 * Players now start out with no materials in their inventory, and have to gather them
 * Picking up blocks
 * Zombies and skeletons - can not spawn with armor
 * Health bar, damage, and dying
 * Signs
 * Pigs, which dropped mushrooms at the time
 * Saplings grow into trees
 * Naturally generating flowers and mushrooms
 * Arrows, which the player spawns with a number of at spawn, and can use them throughout the game
 * Creepers
 * Spiders
 * Mossy cobblestone
 * TNT
 * Bricks
 * Block of iron
 * Obsidian
 * Bookshelves
 * Stone slabs
 * Sheep
 * Rana (removed in Indev)
 * Giants (removed in Indev)
 * Beast Boy, Steve, and Black Steve (removed in Indev)

Trivia

 * Classic was originally named "Minecraft Alpha", but was renamed retroactively upon the release of Alpha.
 * The version numbers used during Early Classic Creative and Multiplayer Test are in the same format as Wurm Online, a game Notch developed from 2003 ( 0.0.#a ).
 * Player skins that are used for the full game are synced with Classic mode. Thus, custom skins can be used in both singleplayer and multiplayer versions of Classic mode for premium users.
 * In the Classic jar files, sprites for several mobs can be found. Playing a Survival Test map in normal Classic will preserve mobs, and also lets the player have multiple blocks of the same type (or none at all) on the hotbar.
 * Classic mode uses very old liquid physics, making it possible to flood the whole map with water or lava from just one block of the liquid.
 * When mobs were added and first survival test was created, it was possible to copy some files into the game client or browser client and play it in classic multiplayer, allowing player to do same things as in survival test, but with other people and on custom maps. However, the mobs appeared in other locations for each client.
 * In Classic mode, the game world is not infinite. It is a cube made out of naturally generated blocks and surrounded by infinite water and bedrock.
 * When Beta 1.8 came out, sounds no longer worked and saving levels to the online server for premium users became impossible because Mojang removed its resources directory and addresses it was referring to for saving, possibly as a step towards phasing it out. Worlds that were not backed up locally were lost.
 * It is possible to obtain lava, water, and grass blocks by using Cheat Engine.
 * The top left corner would display version, FPS, and chunk updates seen the gallery below.
 * The ocean surrounding the map would end at a certain point (not visible in normal play). This end depends on the render distance.
 * The file for 0.30 has 4 random brick textures in the middle of the unused section, and it also contains an uncentered side gold block texture in the lower left hand corner.
 * There was a sound test in 0.0.14a_08 featuring new mining sounds, splashing sounds and a few other new sounds.
 * When the website became unavailable, the save function stopped working also for players with premium accounts.