Reactive Streams comparison

Before we jump into Reactor, let's compare the Streams model with some of the existing similar APIs, such as the java.util.Observable interface and the JMS API. We will try to determine the similarities and the key differences between the APIs.

The Observable interface

The java.util.Observable interface implements the Observer pattern, which can be co-related here. However, all similarities end here. If we look at the Observable interface, we have the following methods:

public class Observable {
  void addObserver (Observer o);
  void deleteObserver (Observer o);
  void deleteObservers();
  void notifyObservers();
  void notifyObserver(int arg);
  int countObservers();
  boolean hasChanged();
}

Let...