Java, non-static cannot be reference to static context

Question

Doing Java course, at UNI atm, and I'm having a bit of trouble with a dice-problem.

I have the following:

 public class Die {
   public int eyes;
   private java.util.Random r;
   private int n;

   public Die (int n) {
     r = new Random();
     this.n = n;
   }

   public void roll() {
     eyes = r.nextInt(Die.n);
   }

When compiling I get: non-static variable n cannot be referenced from a static context. How would I go about fixing this, whilst having it randomize from a user given value?

Take a look at this question's answers: stackoverflow.com/questions/2559527/… .... Of course the question's code is a bit different and less concise, but the answers should still help you. — rodamn
– rodamn, Commented Sep 15, 2015 at 20:56

Evan LaHurd · Accepted Answer · 2015-09-15 20:55:58Z

3

n is not a static variable, so you cannot refer to it in a static manner (Die.n).

Since it is an instance variable in the Die class, and you are referring to it in the Die class, you can just use n instead of Die.n.

answered Sep 15, 2015 at 20:55

Evan LaHurd

9872 gold badges14 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Rasmus Hjorth Lüdeking Over a year ago

Thank you very much! This doesn't completely solve the problem though, seeing as I then get java.lang.NullpointerException: null, in the terminal.

Evan LaHurd Over a year ago

How are you calling roll()? You should be creating a new Die object by using Die die = new Die(6); (or whatever number you want), then you would call die.roll();.

Evan LaHurd Over a year ago

I'd probably also use r.nextInt(n) + 1 otherwise you could get 0, which doesn't make sense for a die.

Rasmus Hjorth Lüdeking Over a year ago

Added Die die = new Die(); to the contructor, still getting nullpointer

Sandeep Chatterjee Over a year ago

The line Die die = new Die(); won't compile since you do not have a no argument constructor for Die class.

Luigi Cortese · Accepted Answer · 2015-09-15 20:52:38Z

1

Remove

Die.n

and change it to simply

If n were declared static, you could use the both notations, even though the first one would be redundant (because you're from the inside of containing class)

answered Sep 15, 2015 at 20:52

Luigi Cortese

11.3k6 gold badges40 silver badges49 bronze badges

Collectives™ on Stack Overflow

Java, non-static cannot be reference to static context

2 Answers 2

5 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related