Read: 04 - OOP

Java OO Tutorial (only the Object and Class ones)

Lesson: Object-Oriented Programming Concepts

• What Is an Object?
  • Object - a software bundle of related state, and behavior that are used to model the real-world objects.
  • Real-world objects - all have state and behavior.
  • Object-oriented programming - is treated like a real-world object, and have a state and behavior.
  • An object stores its state in fields and exposes its behavior through methods.
  • Methods - operate on an object’s internal state and serve as the primary mechanism for object-to-object communication.
  • Data encapsulation - hides internal state and requires all interaction to be performed through an object’s methods.
  • Benefits of bundling code:
    • Modularity - source code for an object can be written and maintained independently of the source code for other objects
    • Information-hiding
    • Code re-use
    • Pluggability and debugging ease
• What Is a Class?
  • Class - a blueprint or prototype from which objects are created, and are models the state and behavior of a real-world object
  • The fields represent the object’s state, and the methods define its interaction with the outside world.

    Java Classes (do NOT do the Nested Classes section)

Classes

• Sample code for a possible implementation of a class:
  • First declare the public class, then put the three fields in the public class.
  • Underneath the fields put the constructor for the class.
  • Underneath the constructor put the methods that you want the class to have.
• Sample code for a possible implementation of a subclass
  • Declare the subclass of the class first.
  • Then give the subclass a field, constructor, and a method.

Binary, Decimal and Hexadecimal Numbers

Binary, Decimal and Hexadecimal Numbers

• Decimals - Every digit in a decimal number has a position, and the decimal point helps us to know which position is which.
• Bases - Base 10 or the Decimal Number System is based on the number 10.
• Counting with Different Number Systems - Count up until just before the “Base Number”, then start at 0 again, but first you add 1 to the number on your left.
  • Binary Numbers - are just “Base 2”, which means you can onlt start counting at 0 and then 1.
  • Hexadecimal Numbers - has 16 numbers, which look the same as the decimal numbers up to 9. After 9 there are the letters A - F in the place of decimal numbers.