Kotlin coroutines example

Coroutines are computer program components that generalize subroutines for non-preemptive multitasking, by allowing execution to be suspended and resumed . Coroutines are well-suited for implementing familiar program components such as cooperative tasks, exceptions, event loops, iterators, infinite lists and pipes.

runBlocking is a coroutine function . … Runs a new coroutine and blocks the current thread interruptible until its completion. This function should not be used from a coroutine. It is designed to bridge regular blocking code to libraries that are written in suspending style, to be used in main functions and in tests.

interface CompletableDeferred<T> : Deferred <T> A Deferred that can be completed via public functions complete or cancel.

Deferred value is a non-blocking cancellable future — it is a Job with a result. It is created with the async coroutine builder or via the constructor of CompletableDeferred class. It is in active state while the value is being computed.

Deferred represents a concept known by other names such as Future or Promise : it stores a computation, but it defers the moment you get the final result; it promises the result sometime in the future.