What is a Non Static Variable and how do I fix them

AlastiAF :

I have a homework assignment where I am supposed to simulate the roll of a dice using math.random() and changing it to an int. I have a single file with 2 classes and am attempting to make an object. My code compiles with the run time error "error: non-static variable this cannot be referenced from a static context." Any Idea what is happening.

I have changed the value of "value" to an integer and successfully ran the code. No other changes have come to mind yet.

public class DieTester_5AlastiCorrigan {

    public static void main(String[] args){

        // New object myDie. 
        Die myDie = new Die();
        System.out.println(myDie.roll());
        System.out.println(myDie.getValue());
    }

    // Creates a new Die Class 
    class Die{
        private String value;

        public Die( int dieRoll ) {
            value = "" + dieRoll;

        }

        // Roll Method chooses random number between 1 - 7 and makes it    an int. 
        public int roll() {
            int max = 6;
            int min = 1;
            int range = max + 1;

            int dieRoll = (int)Math.random()*range;
            //dieRoll = (int)dieRoll;
            return dieRoll;
        }
        // getValue Method returns final value of "value". 
        public String getValue() {
            return value;
        }
    }


}

Expect the console to print out a number 1 <= x < 7 as an integer.

Error message: error: non-static variable this cannot be referenced from a static context Die myDie = new Die(); ^

Sweeper :

Notice how your Die class is inside your DieTester_5AlastiCorrigan class. That makes it an non-static inner class. You would need an instance of DieTester_5AlastiCorrigan to create an instance of Die. So to fix this, simply move Die to the top level, like this:

class DieTester_5AlastiCorrigan {
    ...
}

class Die {
    ...
}

Or add a static modifier:

class DieTester_5AlastiCorrigan {
    ...

    static class Die {
        ...
    }
}

However, there are still a few mistakes in your code. Die has a constructor that takes an int, but when you are creating a Die, Die myDie = new Die();, you are not passing an int to the constructor. I suggest that you add a parameterless constructor:

public Die() {
    this(1);
}

Also, value should not be of type String. It should be an int, and judging from your usage, roll should change the value of value instead of returning the die roll.