RMI. Умножение матрицы на сервере

 import java.rmi.*;
                
public interface MatrixInt extends Remote {
 public void setElement(int row, int column, int value) throws RemoteException;
 public int getElement(int row, int column) throws RemoteException;
 public int getRowsNum() throws RemoteException;
 public int getColumnsNum() throws RemoteException;
 public Matrix multiply(Matrix multiplier) throws RemoteException;
 
}

import java.util.*;
import java.io.*;
import java.io.Serializable.*;
import java.rmi.*;
import java.rmi.server.*;
 
public class Matrix extends UnicastRemoteObject implements Serializable,MatrixInt {
public final int[][] matrix;
public Matrix() throws RemoteException {matrix=new int[0][0];} 
public Matrix(int rows, int cols) throws RemoteException {
if (rows < 1 || cols < 1) {
throw new IllegalArgumentException("Dimensions must be greater than zero");
}
matrix = new int[rows][cols];
}
public void setElement(int row, int column, int value) throws RemoteException {
checkArgumentsIsLegal(row, column);
matrix[row][column] = value;
}
 
public int getElement(int row, int column) throws RemoteException {
checkArgumentsIsLegal(row, column);
return matrix[row][column];
}
 
public int getRowsNum() throws RemoteException {
return matrix.length;
}
 
public int getColumnsNum() throws RemoteException {
return matrix[0].length;
}
 
public void checkArgumentsIsLegal(int row, int column) throws RemoteException {
if (row < 0 || row >= getRowsNum()) {
throw new IllegalArgumentException("Illegal row index");
}
 
if (column < 0 || column >= getColumnsNum())  {
throw new IllegalArgumentException("Illegal column index");
}
}
 
public Matrix multiply(Matrix multiplier) throws RemoteException {
 
int thisRows = getRowsNum();
int thisCols = getColumnsNum();
 
int otherRows = multiplier.getRowsNum();
int otherCols = multiplier.getColumnsNum();
if (thisCols != otherRows) {
throw new IllegalArgumentException("...here could be your ad...");
}
Matrix result = new Matrix(thisRows, otherCols);
 
for (int thisRow = 0; thisRow < thisRows; ++thisRow)
for (int otherCol = 0; otherCol < otherCols; ++otherCol)
for (int thisCol = 0; thisCol < thisCols; ++thisCol) {
result.matrix[thisRow][otherCol] += matrix[thisRow][thisCol]
* multiplier.getElement(thisCol, otherCol);
}
 
return result;
 
}
public static void main(String[]args) throws Exception {
System.out.println("Initializing Matrix...");
MatrixInt matrix=new Matrix();
String matrixName="rmi://localhost/Matrix";
Naming.rebind(matrixName,matrix);
 
}
}

import java.rmi.*;
public class MatrixClient {
 
/**
* @param args
* @throws IOException
* @throws NumberFormatException
*/
public static void print(Matrix matrix) throws RemoteException {
int rows = matrix.getRowsNum();
int cols = matrix.getColumnsNum();
System.out.println("Matrix dimensions: [" + rows + "; " + cols + "]");
for (int i = 0; i < rows; ++i) {
for (int j = 0; j < cols; ++j) {
System.out.print(matrix.getElement(i, j) + " ");
}
System.out.println();
}
}
public static Matrix fill(Matrix matrix) throws RemoteException {
for (int i = 0; i < matrix.getRowsNum(); ++i) {
for (int j = 0; j < matrix.getColumnsNum(); ++j) {
 
matrix.setElement(i, j, (int) (Math.random() * 10));
}
}
return matrix;
}
public static void main(String[] args) throws Exception {
String objectName="rmi://"+args[0]+"/MatrixInt";
System.out.println("Starting...\n");
MatrixInt first=(MatrixInt)Naming.lookup(objectName);
MatrixInt second=(MatrixInt)Naming.lookup(objectName);
System.out.println("done"); 
first = new Matrix(1, 2);
 
fill((Matrix)first);
print((Matrix)first);
second = new Matrix(2, 3);
fill((Matrix)second);
print((Matrix)second);
 
Matrix mul = (Matrix)first.multiply((Matrix)second);
 
print(mul);
 
}