Do I have to use class name instead of instance name when trying to access a static member?

[Momen Travolta]

I wanted to try an example of my book, here is the code:-

package javaapplication17;

public class Main {

    public static void main(String[] args) {

        Circle2 c1 = new Circle2();

        System.out.println("Before creating c1");
        System.out.println("c1 is : radius (" + c1.radius + ") and number of Circle objects (" + c1.numberOfObjects + ")");

In a second file:-

package javaapplication17;

public class Circle2{

    double radius;
    static int numberOfObjects = 0;

    Circle2() {
       radius = 1.0;
       numberOfObjects++;
    }

    static int getNumberOfObjects() {
        return numberOfObjects;
    }
}

I got this message after trying to compile to the code (using NetBeans)
:-

[Joachim Rohde]

You don't have to, but you should:

Class variables are referenced by the class name itself, as in

Bicycle.numberOfBicycles

This makes it clear that they are class variables.

Note: You can also refer to static fields with an object reference like

myBike.numberOfBicycles

but this is discouraged because it does not make it clear that they are class variables.

(source: http://java.sun.com/docs/books/tutorial/java/javaOO/classvars.html)