public interface IMatrixMultiple {
    public int[][] mmltiple(int[][]a ,int [][]b);
}
?public class MatrixMultiple implements IMatrixMultiple {

    @Override
    public int[][] mmltiple(int[][] a, int[][] b) {
        int [][] result = new int[a.length][b[0].length];
        for (int i = 0; i<a.length; i++) {
            for (int j = 0; j<b[0].length; j++) {
                for (int k = 0; k<a[0].length; k++) {
                    result[i][j]= result[i][j]+a[i][k]*b[k][j];
                }
            }
        }
        return result;
    }
}