Java default interface methods concrete use cases

Question

Java 9 is near to come and more features will be added to Java interfaces, like private methods. default methods in interfaces were added in Java 8, essentially

Answer 1

Removing the Default-Adapter of Listener by using Default Methods

Sometimes, we need to introduce a default Adapter class for the java.util.EventListener which has multiple events need to trigger, but we only interested in some of events. for example: swing create each *Adapter class for each *Listener.

I recently found this is very useful when we declare listeners with default methods we can remove the middle adapter class. for example:

interface WindowListener extends EventListener {

    default void windowOpened(WindowEvent e) {/**/}

    default void windowClosing(WindowEvent e) {/**/}

    default void windowClosed(WindowEvent e) {/**/}
}