How to get events from other objects?

Question

Java

Good afternoon! Tell me who knows how this is done, is there some kind of pattern or what is better?
For example, there is an interface with some events (newEvent, deleteEvent) that receive them through WSS. This interface is implemented by different classes.
And I need a class that can handle all these events. That is, it should be one method that will immediately see these events.
What is the best way to do this? Despite the fact that the first two classes do not know anything about the class that will process them.

Answer 1

Observer in Java