JAVA Objects & Classes

JAVA Objects & Classes

1. Classes

   • blueprint or template to create objects of identical types
   • determines what objects you get
   • consider 3 things:
     • class name
     • fields
       • variables // primitive or references
         • EX: age, salary
     • methods
       • defines actions that a class's object can do // declaration part & body
         • declaration
           • return value, method name, list of arg
         • body
           • code to perform action
         • return type:
           • primitive
           • object
           • void
         • method main
           • provides entry point to application
   • must have AT LEAST one constuctor
     • used to construct an object // looks like a method
       • doesn't have a return value (not even void)

2. Object (Instance)

   • two features
     • attributes OR fields
     • actions OR methods
   • model to represent a real-life situation
   • "new" keyword followed by constructor of the class used to create object
   • use reference variables to manipulate later
     • need to declare an object reference with the same type as the object