OBJECT

OBJECT

1. can have attributes (called Fields in JAVA)

   • FIELDS
     • AKA variables
     • can also refer to another object
     • THE NULL KEYWORD
       • when a reference variable does not have a value, it is called null
         • used == operator to test if a reference variable is null

2. can perform actions (called METHODS in JAVA)

   • METHODS
     • actions a class's objects can do
     • have a declaration and body
       • declaration consists of return value, method name, and list of arguments
         • return value can be an object or void, meaning it receives no return
       • body contains code to perform the action
     • METHOD MAIN
       • provides the entry point to an application

3. blueprint or template used to create objects of identical type

   • CLASS
     • declaration of a class in JAVA must use the keyboard class, a class name, and a body between braces
     • capitalize initial of each word by convention
     • INSTRUCTOR
       • every class must have at least one in order to create objects
       • looks like a method, but does not have a return value
       • must have the same name as the class

4. create a new object by using the new keyword followed by the class constructor

   • may want to assign it to a field or variable