Is a techinique for formally proving the correctness of a program.

You develop the correctness proof of the program as you are wirting the code.

Give input I the output should be "o"

Carefully crafted tests cases, if the program works correctly for all of the cases,

Three Steps:Unit Testing, Integretion Testing, Black Box Testing

 As we finish each program unit, we thoroughly test it with chosen set of data.

    -Flow Path

    -Clear Box Testing

A unique execution sequence throuhg a program unit

-Each subclass may override a method

-Superclass specifies what and how

-Models an IS-A Relationship

-Specialization and Extension

Inheritance of Interface

-Interface refers to what operations can be performed on an object.

-Used just to define a set of operations that a subclass must implement

-the superclass defines the behavior that is implemented in the subclass, but not in the superclass.

-The subclass inherits the specification of its superclass's behavior

-What the subclass must do, but not how to do it

The subclass is a specialized form of the superclass, but satisfies the specification of the parent class.

-is a relationship

-Subclass is more specialized

-both behavior and implementation

Abstract: there are fields that all subclasses will need

-At least one method can be given an implementation that some subclasses can inherit.

Interface: a small number of methods define a role many different kinds of objects can play

-when the role may be mixed in with other roles