BOOK NOTES
CHAPTER 9 - STATIC

9.6 STATIC METHODS

- static/class method: not invoked on an object
- instance methods operate on a particular instance of a 
  class
- motivation: encapsulate computation that involves only 
  numbers (which can't invoke methods)
- call: use the name of the class instead of the name of the 
  object
- main must be static because there are no objects when the 
  program starts
- declare with the static modifier
- minimize use of static methods

9.7 STATIC FIELDS

- store values outside a particular object
- single value that is the same for the entire class
- declare with the static modifier
- aka class field
- every method of a class can access static fields of the 
  same class
- initialze when declare
- created when class is loaded
- always declare private (unless a constant)
- minimize use of static fields