This is the error I'm getting.

Exception in thread "main" java.lang.StackOverflowError

at knapsack.knap.knap(knap.java:16)

I would really apprciate the help. Thanks in advance.

```
package knapsack;
import javax.swing.JOptionPane;
public class knap {
static int N; // Number of items
static int [] size;
static int [] val;
static int [] maxKnown; // Value for best knapsack of a weight
static int [] itemKnown; // Item that brought us up to the weight
static int knap(int M){
int i, space, max=Integer.MIN_VALUE, maxi = 0, t;
if (maxKnown[M] >= 0)
return maxKnown[M];
for (i = 1; i <= N; i++)
if ((space = M-size[i]) >= 0)
if ((t = knap(space) + val[i]) > max){
max = t;
maxi = i;
}
maxKnown[M] = max;
itemKnown[M] = maxi;
return max;
}
public static void main(String[] args){
int cap = Integer.parseInt(JOptionPane.showInputDialog("What is the capasity of the bag?")), wt;
N = Integer.parseInt(JOptionPane.showInputDialog("How many items?"));
size = new int [N + 2];
val = new int [N + 2];
maxKnown = new int [cap + 1];
itemKnown = new int [cap + 1];
for (int i = 0; i < N; i++){
size[i] = Integer.parseInt(JOptionPane.showInputDialog("Size of item #" + (i+1) + "?"));
val[i] = Integer.parseInt(JOptionPane.showInputDialog("Value of item #" + (i+1) + "?"));
}
System.out.println ("Capacity: " + cap);
System.out.println ("\nAvailable items:");
for (int i = 0; i < N; i++)
{
System.out.printf("%d: (%d size, %d val)\n", i, size[i], val[i]);
}
N++;
size[N] = 1;
val[N] = 0;
for (int i = 1; i <= cap; i++)
maxKnown[i] = -1;
System.out.print("\nOptimal value is ");
System.out.println(knap(cap));
for ( wt = cap; wt > 0; )
{
int i = itemKnown[wt];
System.out.printf ("%d: (%d wt, %d val)\n", i, size[i],val[i]);
wt -= size[i];
}
}
}
```