[JAVA] Transpozycja Macierzy

package matrix;

  import java.util.Random;

    public class Matrix {
   private int[][] _matrix;

   public Matrix(int n, int m) {
      _matrix = new int[n][m];
   }

   public Matrix(int n) {
      this(n, n);
   }

   public void print() {
      for (int i = 0; i < _matrix.length; i++) {
          for (int j = 0; j < _matrix[i].length; j++) {
              System.out.print(" " + _matrix[i][j]);
          }
          System.out.println("");
      }
   }

   public void fillRandom() {
      Random rand = new Random();
      for (int i = 0; i < _matrix.length; i++) {
          for (int j = 0; j < _matrix[i].length; j++) {
             _matrix[i][j] = rand.nextInt(9);
          }
      }
   }

   public Matrix transpose() {
      Matrix matrix = new Matrix(_matrix[0].length, _matrix.length);
      for (int i = 0; i < _matrix.length; i++) {
          for (int j = 0; j < _matrix[i].length; j++) {
             matrix._matrix[j][i] = _matrix[i][j];
          }
      }
      return matrix;
   }

    public static void main(String[] args) {
      Matrix m = new Matrix(3, 3);
      m.fillRandom();
      m.print();
      System.out.println("");
      Matrix transpose = m.transpose();
      transpose.print();
    }
}