Kotlin deferred to CompletableFuture

Coroutine suspends the thread and does not block it so that it can switch to another work .

Coroutines are nothing but lightweight threads. They provide us with an easy way to do synchronous and asynchronous programming . Coroutines allow us to replace callbacks and build the main safety without blocking the main thread.

Why you should use Coroutines in the first place? They provide a way to write asynchronous code in a sequential manner, making our code much easier to read . In some way, they are similar to threads, but they are much more efficient, as multiple coroutines can run on a single thread.

CoroutineScope. common. interface CoroutineScope. Defines a scope for new coroutines . Every coroutine builder (like launch, async, etc.) is an extension on CoroutineScope and inherits its coroutineContext to automatically propagate all its elements and cancellation.

Threads. Coroutines are very similar to threads. However, coroutines are cooperatively multitasked, whereas threads are typically preemptively multitasked. Coroutines provide concurrency but not parallelism .