This build creates a mob trap that lures and eliminates mobs automatically for drops. It is efficient, compact, and useful ...

Minecraft Tutorial - How to Create a Mob Trap and Item Collection Machine by drunkoncustard. Note that to speed up the process, this machine was created in Minecraft's Infdev mode.

There are a handful of reasons someone might want to build an efficient villager farm in their Minecraft world. Perhaps, they've grown bored of simply surviving, just to vanquish the Ender Dragon time ...