An interface is best explained with an example. The most common example is the connections among a television, a remote control, and a user. A user turns on the TV by using the remote control and may not necessarily know anything about the TV’s wiring. Thus, the remote control is an interface between the user and the television set.

Similarly, when a class implements an interface, the method functionalities are implemented without knowledge of the method's inner workings.

The following are examples of when to use an interface:

• When two or more unrelated classes implement a set of methods, which may be defined in an interface and then implemented by the classes.
• When an interface is a good alternative to multiple class inheritance.
• When an object’s functionality is revealed without described implementation.