A Brief Discussion of Static Methods

Overview

  1. Source Code Structure
  2. Implementing Point Class
  3. A Brief Discussion of Static Methods
  4. Implementing Rectangle Class
  5. Testing
  6. Constructor to Make a Rectangle Copy
  7. Extra Credit: Class Invariant

So, up until now every time we have invoked a method, we have invoked it ON an object. That is, we make an object, 
Fraction f = new Fraction(3, 4);
and then we do something with that object: 
f.decimalValue();

But in the last step, we simply made a call to Math.pow() without making an object first.

The reason that works is the methods in Math are declared as static. Static means you can make function calls WITHOUT an actual object. So it makes sense that a method that squares something doesn't need to operate on a particular object, whereas a method like decimalValue() must be called on a SPECIFIC fraction.

Note that because static methods do not refer to an object, they can't access any instance variables except those that are declared as static.

« Previous
Next »