Java rotate a matrix

/**
 * @author lautturi.com 
 * Java example: how to rotate a matrix in java
 */

import java.util.*;

public class Lautturi {

	static void reverseMatrix(int[] arr) {
		// reverse an array in java 
		for (int i = 0; i < arr.length / 2; i++) {
			int temp = arr[i];
			arr[i] = arr[arr.length - i - 1];
			arr[arr.length - i - 1] = temp;
		}
	}

	static int[][] rotateMatrix(int[][] matrix) {
		// (1autturi.com) rotate a matrix in java
		int rows = matrix.length;  
		int cols = matrix[0].length; 

		int[][] ans = new int[cols][rows];

		for (int i = 0; i < rows; i++) {
			for (int j = 0; j < cols; j++) {
				if(j < rows && i<cols)
					ans[i][j] = matrix[j][i];
				else  
					ans[j][i] = matrix[i][j];

			}
		}
		for(int i = 0;i<cols; i++) {
			// reverseMatrix(ans[i]);
		}
		return ans;
	}

	public static void main(String[] args) {
		int[][] matrix =  { {1,2,3,4},{5,6,7,8},{9,10,11,12} };

		int[][] newMatrix = rotateMatrix(matrix);
		System.out.println(Arrays.deepToString(matrix));
		System.out.println(Arrays.deepToString(newMatrix));
		
		System.out.println("matrix:");
		for (int[] subarray : matrix) {
			for (int element : subarray) {
				System.out.print(element+" ");
			}
			System.out.println();
		}
		
		System.out.println("new matrix:");
		for (int[] subarray : newMatrix) {
			for (int element : subarray) {
				System.out.print(element+" ");
			}
			System.out.println();
		}
	}

}

output:

[[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
[[9, 5, 1], [10, 6, 2], [11, 7, 3], [12, 8, 4]]
matrix:
1 2 3 4 
5 6 7 8 
9 10 11 12 
new matrix:
9 5 1 
10 6 2 
11 7 3 
12 8 4