What is adapter in programming language?

Answer 1

An adapter is a class that subclasses a commonly used class or interface with reasonable default functions provided. For example, the WindowAdapter provides a quick solution that provides default do-nothing functions for 4 common interfaces that a GUI would use. Typically, a developer only needs one or two functions from WindowEvent, for example, but without an adapter, they are required to implement seven functions (with five or six of them "do-nothing" functions), instead of just using an adapter and providing the one or two function bodies they do need.