The Observer Pattern is a behavioral design pattern used to define a one-to-many dependency between objects. When one object (the subject) changes its state, all dependent objects (observers) are notified and updated automatically. This pattern is commonly used in scenarios where changes in one part of an application need to be reflected in other parts without tightly coupling the components. Components of the Observer Pattern: Subject: The object that maintains a list of observers and notifies them of any changes. Observer: The interface or abstract class that defines the update method, which is called when the subject’s state changes. ConcreteSubject: A class that implements the Subject interface and maintains the state of interest. ConcreteObserver: A class that implements the Observer interface and updates itself based on the subject’s state. Simple Example in Java: Let’s create a weather monitoring system where a WeatherStation (subject) notifies multiple display devices (observers) of changes in weather conditions. ...