Abstraction is the basis for good Object-Oriented design that is modular, reusable, and maintainable.

Interfaces and Abstract classes are two mechanisms in Java that provide high-level abstractions. An interface or abstract class is something which is not concrete, something which is incomplete.

For this discussion, what do you think is meant by “Programming to an interface”? What are some differences between Abstract Classes and Interfaces? Provide a simple example application with an interface definition and a class which implements the interface.