Object Oriented Programming

Object Oriented Programming

1. UML Diagrams

   • Diagram that represents a class by name, fields, and methods.
   • Java Classes
     • Blueprint used to create objects of identical type. Ex: class Employee{            int age;            double salary;             }
     • Constructor
       • Every class must have at least one constructor. Used to create objects. Do not have a return value. Must have the same name as class. Ex: constructorName (list of arguments{            [constructor body]            }
       • Java Objects
         • Instance of a class. Correspond to the properties of a class. Fields and methods are both optional.
         • Fields
           • Variables. Can be primitives or references to objects. Syntax: Capitalize initial except for first word. Ex: numberOfRows
         • Methods
           • Defines the actions that a classes objects can do.
           • Declaration
             • Consists of return value, method name, and list of arguments Ex: "returnType methodName (list of arguments"
           • Body
             • Contains the code the performs the action.
           • Method Main
             • Provides entry point to application. Apps have many classes, but only one needs a main method. Signature is "public static void main (String[ ] args)"