Spring 5.0 By Example

Let's play with the Reactor

To understand it better, let's play with the Reactor. We will implement and understand the difference between hot and cold publishers in practice. 

Cold publishers do not produce any data until a new subscription arrives. In the following code, we will create a cold publisher and the System.out:println will never be executed because it does not have any subscribers. Let's test the behavior:

@Testpublic void coldBehavior(){  Category sports = new Category();  sports.setName("sports");  Category music = new Category();  sports.setName("music");  Flux.just(sports,music)      .doOnNext(System.out::println);}

As we can see, the method subscribe() is not present in this snippet. When we execute the code, we will not see any data ...