What is the relationship between an event-listener interface and an event-adapter class?

The relationship between an event-listener interface and an event-adapter class in Java is fundamentally about simplifying the implementation of event handling in applications, particularly when not all methods of the listener interface are needed.

An event-listener interface in Java defines a set of methods that correspond to different types of events that can occur within a program. Each method in the interface is designed to handle a specific type of event. For example, the MouseListener interface includes methods like mouseClicked(), mouseEntered(), and mouseExited() among others, each triggered by different mouse actions[4][5].

However, directly implementing an event-listener interface can be cumbersome because it requires the implementation of all methods in the interface, even if only a few are actually needed for the specific application. This is where the event-adapter class comes into play. An event-adapter class provides default implementations (usually empty) for all methods defined in an event-listener interface. This allows a developer to only override and implement the methods that are actually needed[1][2][3][4][5].

For instance, if a developer only needs to handle mouseClicked() events, instead of implementing all methods of the MouseListener inter...