Use 2-dimensional arrays to represent matrices.
Compute the product of the matrices and store the data in a new 2-dimensinal array.
Print the product of Matrix A Row 2 and Matrix B Column 1.
You want to multiply A and B, to find the product matrix C. For ease, assume that (for now) you only want to compute the value at row 2, column 1, in the product matrix C.
But, to compute the value in row2, column 1, of the matrix C, you will need to compute the “dot product” of A’s entire row 2, and B’s entire column 1:

My program is telling me that my Array Index is out of bounds with an exception at 4, but I'm not sure how to solve it

```
public class lab
{
   public static void main(String[] args)
   {

      int[][] A = { {10,55,4,89,39} , {45,9,49,98,23} , {4,8,90,23,9} 
{8,32,80,2,31} };

      int[][] B = { {10,55,4,89,39} , {45,9,49,98,23} , {4,8,90,23,9} , {8,32,80,2,31} };

      int[][] C = new int[A.length][B[0].length];

      int sum = 0;

      for (int i = 0 ; i < 5 ; i++)
      {
         sum = sum + A[2][i]*B[i][1];
      }

      C[2][1] = sum;

      System.out.println(sum);

   } // end main
} // end class

```

The output should be:

1616