Java Swing observer pattern

Observer is a behavioral design pattern that allows some objects to notify other objects about changes in their state . The Observer pattern provides a way to subscribe and unsubscribe to and from these events for any object that implements a subscriber interface.

Ans: The Observable class and the Observer interface have been deprecated in Java 9 because the event model supported by Observer and Observable is quite limited, the order of notifications delivered by Observable is unspecified, and state changes are not in one-for-one correspondence with notifications.