Java Printing int array returns gibberish?

public class ArrayMultiplication {
	public static void main (String args []){
	int [][]a={{1,6,2},{4,18,3},{5,8,4}};
	int [][]b= {{9,12,13},{6,9,7},{32,4,3}};
	int [][]product = multiply (a,b);
	System.out.println (""+product);
	}
	public static int [][] multiply (int [][]a, int[][]b){
		int aRows=a.length;
		int aColumns=a[0].length;
		int bRows=b.length;
		int bColumns=b[0].length;
		if (aRows != aColumns || bRows != bColumns) {
			return null; 
		}
		int[][]resultantProduct = new int [aRows][aColumns];
		for (int i=0; i<aRows; i++) {
			for (int h=0; h<aColumns; h++) {
				resultantProduct [i][h] += a[i][h] * b[i][h];
			}
		}
		return resultantProduct;
	}
}