What are Handlers in Android?

A Handler is used to send and process Message and Runnable objects associated with a thread's MessageQueue. When a Handler created default bound with a Looper class. It will deliver messages and runnable to that Looper's message queue and execute them on Looper's thread.

Handlers are mainly used to Update the User Interface from a background thread, Enqueue a task for a different thread and Schedule a task for a specified time.