Hands-On Reactive Programming in Spring 5

Generating an asynchronous sequence

RxJava makes it possible to generate not only one event in the future, but an asynchronous sequence of events based, for example, on a time interval, as shown in the following code:

Observable.interval(1, TimeUnit.SECONDS)   .subscribe(e -> System.out.println("Received: " + e));Thread.sleep(5000);                                                  // (1)

In that case, the output is as following:

Received: 0Received: 1Received: 2Received: 3Received: 4

Also, if we remove Thread.sleep(...) (1), our application will exit without any output. This happens because events would be generated and therefore consumed in a separate daemon thread. So, to prevent the main thread from finishing the execution, we may sleep() or do some other useful tasks.

Of course, there ...