Creating a Matrix given arrays of the same dimensions

[math8]

say I have two int arrays of length 3 (ex: a = [ 1 2 3] and b = [4 5 6])
I would like a method that returns the 2x3 Matrix:

M =

1 2 3
4 5 6.

I have tried using

public int[][] createMatrix(int[] a, int[] b){
                   double[][] M = new double[2][a.length];
                   for(int i = 0; i < 2; i++){
                        for (int j = 0; j <a.length; j++){
                              M[i][j] = a[j]; 
                        }
                   } 
           return M; 
           }

I have two problems with the code above:
1)Is there a way to 'count' the number of arguments this method has? As opposed to writing '2' in

for(int i = 0; i < 2; i++)

, I think that would be better if it was something like

for(int i = 0; i < 'number of arguments in this method'; i++)

2)Well, I can see that the matrix M above will be
123
123
for the simple reason that I have not used the array b anywhere in the code. I am not sure how I can incorporate b in the inner loop.


Any help is appreciated.