scala - Difference Await.ready and Await.result

Question

I know this is quite an open ended question and I apologize.

I can see that Await.ready returns Awaitable.type while Await.result returns T but I still confuse them.

What are the difference between the two?

Is one blocking and the other one non-blocking?

question from:https://stackoverflow.com/questions/41170280/difference-await-ready-and-await-result

Answer 1

They both block until the future completes, the difference is just their return type.

The difference is useful when your Future throws exceptions:

def a = Future { Thread.sleep(2000); 100 }
def b = Future { Thread.sleep(2000); throw new NullPointerException }

Await.ready(a, Duration.Inf) // Future(Success(100))    
Await.ready(b, Duration.Inf) // Future(Failure(java.lang.NullPointerException))

Await.result(a, Duration.Inf) // 100
Await.result(b, Duration.Inf) // crash with java.lang.NullPointerException