- · Variables come in two flavors: primitive and reference.
- · Variables must always be declared with a name and a type.
- · A primitive variable value is the bits representing the value (5, ‘a’, true, 3.1416, etc.).
- · A reference variable value is the bits representing a way to get to an object on the heap.
- A reference variable is like a remote control.
- · Using the dot operator (.) on a reference variable is like pressing a button on the remote control to access a method or instance variable.
- A reference variable has a value of null when it is not referencing any object.
- An array is always an object, even if the array is declared to hold primitives. There is no such thing as a primitive array, only an array that holds primitives.
· Methods
o
void
speak(){}
o
Call
method with (.)
o
Methods
have ( ) when called
o
Ex.
person1.speak( );
· Getters and Return Values
o
Getters
§
Ex. public int getAge( ){
Return age;
§
Must
return correct type
· Method Parameters
o
Inside
( ) are parameters
o
Call
a method
o
(int
value) or ( String name)
o
Person1.name
= “Jael”
·
Setters and "this"
o
Ex.
void setAge (int age){
this.age; }
 |
| This is the people class that shows the instance variable name being declared private and I use my getters and setters in my greeting method. |
· Encapsulation: Public, Private, Protected
o
Public = can access anywhere
o
Private = access in same class only
o
Protected = can be accessed in sub-classes and
packages
o
No modifier = same package only
|
| This is the people class that shows the instance variable name being declared private and I use my getters and setters in my greeting method. |
 |
| This is the programs main method and here I instantiate a people array and use my setter and getters to produce a greeting statement with user input. |
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