Adapter Design Pattern in Java

Adapter design pattern lets unrelated classes communicate and work with each other.It achieves this objective by creating new interfaces for creating compatibility amongst otherwise non communicable classes.

The adapter classes in Java API are WindowAdapter,ComponentAdapter, ContainerAdapter, FocusAdapter, KeyAdapter, MouseAdapter and MouseMotionAdapter.

In case of listener interfaces,whenever a class implements such an interface, one has to implement all of the seven methods.In case of WindowListener interface,it has seven methods.WindowAdapter class implements WindowListener interface and make seven empty implementation. When a class subclasses WindowAdapter class, one may choose the implementation of a method as per one's choice of implementation.

Adapter design pattern is also referred as Wrapper pattern when it is introduced by composition of classes.