Go4Expert - Adding array elements

For some reason, the last line doesn't work at all. :confused: I've looked through different forums and kept finding the same code for adding the integers in an array, but nothing happens.

Code:

    public static void main(String[] args)

    {

        int[][] array2D = {{0,1,2,3},{4,5,6,7},{8,9,10,11},{12,13,14,15}};

        

        for (int row=0; row<array2D.length; row++)

        {

            for (int col=0; col<array2D[row].length+1; col++)

            {    

                if (col<array2D[row].length)

                {

                    System.out.print(array2D[row][col] + "\t");

                }

                else

                    System.out.println();

            }

        }

        int sum = 0;

        for (int i=0; i<array2D.length; i++){

            sum += array2D[i]; //this one has the error

        }

        System.out.println ("The sum of all the elements is: " + sum);

I've just started learning Java this month, so I really need the help. Thanks!