layout	title	folder	permalink	categories	tags
pattern	Callback	callback	/patterns/callback/	Other	Java Difficulty-Beginner Functional Idiom

Intent

Callback is a piece of executable code that is passed as an argument to other code, which is expected to call back (execute) the argument at some convenient time.

Applicability

Use the Callback pattern when

• when some arbitrary synchronous or asynchronous action must be performed after execution of some defined activity.

Real world examples

• CyclicBarrier constructor can accept callback that will be triggered every time when barrier is tripped.