Why is this producing a java.lang.StackOverflowError and what does that mean?

Question

I wrote a simple code for a craps game. I'm still figuring out how to work out the looping glitches, but it is giving me a java.lang.StackOverflowError at line 33:
//display the value of dice System.out.println("You rolled " + die + "+ " + die2 + ". Totalling " + dice);.

Here is the code:

 /**
 * A simulation of the craps betting game.
 * 
 * @
 * @
 */
import java.util.Random;



public class Craps
{
    //random number generator
    private Random randomNumber = new Random();

    //roll the dice
    public int rollDice()
    {
        //first die
        int die = (randomNumber.nextInt(6) + 1);

        //second die
        int die2 = (randomNumber.nextInt(6) + 1);

        //add die + die2
        int dice = die + die2;

        //point value
        int myPoint = 0;

        //display the value of dice
        System.out.println("You rolled " + die + "+ " + die2 + ". Totalling " + dice);

            if (dice == 7) {
                System.out.println ("Congratulations, YOU WIN!");
        }
        if (dice == 11) { 
            System.out.println ("Congratulations, YOU WIN!");
        }

            if (dice == 2) {
                System.out.println ("I'm sorry, you lose.");
    }
    if (dice == 3) {
        System.out.println ("I'm sorry, you lose.");
    }
    if (dice == 12) {
        System.out.println ("I'm sorry, you lose.");
    }

        else {
            System.out.println ("And the game continues...");
            myPoint = dice;
            if (dice == 7) {
                System.out.println ("I'm sorry, you lose.");
            }

        while (dice != 7)
        {
         rollDice();

            if (dice == myPoint) {
                System.out.println ("Congratulations, YOU WIN!");
            }
            else {
                myPoint = dice;
            }
        }
    }
    return dice;
}

}

Are you trying to do this recursively? That `while(dice != 7)` loop looks like it should go outside the method otherwise. — ironicaldiction, Dec 19 '13 at 04:29

score 1 · Answer 1 · answered Dec 19 '13 at 04:22

1

Because you're growing the stack frame when you call rollDice() recursively. You eventually run out of space to continue. You should return an int from your method, and use a loop to call it (perhaps infinitely).

answered Dec 19 '13 at 04:22

Elliott Frisch

198,278
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He needs a condition to exit the method, using the same method even if he changes it to a loop it will run forever – Pita Dec 19 '13 at 04:24
@PIta `true`. But it wouldn't produce a `StackOverflowError`. – Elliott Frisch Dec 19 '13 at 04:24

score 0 · Answer 2 · answered Dec 19 '13 at 04:23

0

You are not properly returning from rollDice function, You keep calling it recursively. You need a proper exit condition for the method.

answered Dec 19 '13 at 04:23

smk

5,340
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score 0 · Answer 3 · edited May 23 '17 at 12:28

Try this...

 while (dice != 7)
    {
      dice  = rollDice();
      // ...
    }

The problem in your code is, because dice is a local variable of rollDice(), recursive call to rollDice() does not change the value of dice in the current function call. Therefore, the while loop never exits. So, recursive calls to the function pile up and fills your stack.

This error message simply means your stack memory is full. Java limits the size of the stack memory to a certain maximum number of bytes. When recursive function calls pile up and fills it, at some point, there will not be enough memory available on the stack to the next function call. At this point java throws this error.

I suggest you to read more about stack and heap memories.
Check What and where are the stack and heap?

Why is this producing a java.lang.StackOverflowError and what does that mean?

3 Answers3