Course Notes Set 1: Java and OO Review

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Course Notes Set 1Java and OO Review

• COMP 2210
• Dr. Hendrix
• Computer Science and Software Engineering
• Auburn University

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Object-Oriented Programming

• Programming world-view
• Things in the problem space modeled in software
  as objects.
• An object is an abstraction of a real-world
  thing, implemented as an encapsulation of private
  data and methods (operations on that data).

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Messages and Methods

• Objects communicate by sending messages to one
  another.
• Receiving a message causes a method to execute.
• An object-oriented program defines a collection
  of objects that communicate and cooperate to
  solve a problem.

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Classes and Instances

• Class - a description of an entire category or
  group of objects.
• Every object is an instance of some particular
  class.

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Inheritance

• New classes are derived from existing ones
  through inheritance.
• Subclasses inherit all the data and methods of
  their superclass.
• Subclasses can add new data and methods and
  override existing methods.

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Controlling Inheritance

• Visibility modifiers affect how data and methods
  are inherited
• public, protected, private, abstract, final

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Polymorphism

• Refers to the ability of an object reference to
  take many forms.
• This derives from Javas typing rules for
  reference variables and its implementation of
  dynamic dispatching.