Write a static method rotateMatrix that accepts a two-dimensional (2D) integer array as square matrix NxN (i.e., N rows and N columns), and returns a 2D integer array as square matrix after rotating the input matrix by 90 degrees in clockwise direction.

For example, if input 4x4 integer matrix is:

{{1, 2, 3, 4},

{5, 6, 7, 8},

{9, 10, 11, 12},

{13, 14, 15, 16}}

After rotation, rotateMatrix should return the following 2D integer array:

{{13, 9, 5, 1},

{14, 10, 6, 2},

{15, 11, 7, 3},

{16, 12, 8, 4}}

For example, if input 2x2 integer matrix is:

{{1, 2}, {5, 6}}

After rotation, rotateMatrix should return the following 2D integer array:

{{5, 1},

{6, 2}}

Note: NxN matrix is declared as "int array_name[N][N];". E.g., 4x4 matrix would be "int array_name[4][4];".