Computer

• Object-Oriented Programming (OOP) is a programming methodology that defines objects whose behaviors and interactions accomplish a given task
• Object:

  • An object has characteristics or attributes
  • The values of an object's attributes give the object a state
  • The actions that an object can take are called behaviors, defined by methods
• Class:

  • Objects of the same kind have the same data type and belong to the same class
  • A class defines a kind of object; it is a blueprint for defining objects
  • The data type of an object is the name of its class
• Inheritance:

  • Organizing classes through inheritance
  • Allows objects of a class to take on the properties of objects from another class
  • Used to avoid repetition of programming instructions for each class
  • To apply inheritance between classes, the extends keyword is used
• Interface:

  • A program component containing the heading for a number of public methods
  • Some interfaces describe all public methods in a class, while others specify only certain methods
  • Used by another class through the implements keyword
• Package:

  • A collection of related classes and interfaces grouped together into a folder
  • The name of the folder is the name of the package
  • Classes in the package are placed in separate files, with the file name beginning with the class name
  • All classes in a package can be used within any program or class definition by placing an import statement
  • The class does not need to be in the same folder as the classes in the package
  • Syntax for importing: import package_name.class_name_or_asterisk