Bucket

Buckets are tools used to carry water, lava, milk and fish (cod, pufferfish, salmon, and tropical fish only.)

Usage
Empty buckets can be used to "pick up" a water or lava source block by pressing item on a block of the relevant type.

Similarly one can press when looking at a cow or mooshroom to fill a bucket with milk.

Empty buckets can also be used to collect fish in buckets.

A bucket filled with a source block can then be used to place its source block contents in the empty block next to the side of the block the player is currently looking at, or replacing the block looked at for some replaceable blocks.

A bucket full of milk can only be emptied by drinking it or by using it in crafting a recipe (like cake).

An empty bucket can be used to empty a cauldron with water, filling the bucket with water. This does not work with dispensers.

An empty bucket can be used to empty a cauldron with lava, filling the bucket with lava. This does not apply to Java Edition.

ID




Item data
$$, buckets usually use data values to determine contents. Once used, each data value is set to 0 (Empty Bucket). If no data value is provided, the data value is 0. However, if a player picks up a fish with a bucket, the NBT data of the bucket contains the full entity data of the fish picked up.

Trivia

 * An empty bucket fills with water when placed in the fuel slot of a furnace while smelting a wet sponge.