java.rmi.UnmarshalException; on client side

[bigmac15]

//implementation of the remote interface

import java.rmi.*;
import java.rmi.server.*;
import java.sql.*;
import java.util.ArrayList;
import java.net.*;
import java.io.*;
import java.applet.*;
import java.io.Serializable;

class DuplicatedAddressException extends RemoteException implements Serializable {
	DuplicatedAddressException() { }
	DuplicatedAddressException(String s) { super(s); }
}

public class DataAccessImpl extends UnicastRemoteObject implements DataAccess
{
	private String name;
	static final String driverName = "com.mysql.jdbc.Driver";
	static final String sysName = "zenit.senecac.on.ca";
	static final String dbName = "--";
	static final String userId = "--";
	static final String password = "--";
	private ArrayList alAddress = new ArrayList();
	private ArrayList alX = new ArrayList();
	private ArrayList alY = new ArrayList();
	private Connection conn;
	
	
	
	public DataAccessImpl(String s) throws java.rmi.RemoteException
	{
		name = s;
		try
		{
			Class.forName(driverName);
		}
		catch(ClassNotFoundException ec)
		{
			ec.printStackTrace();
			System.out.println("MySQL JDBC driver not found!");
			System.exit(1);
		}
		System.out.println("JDBC class found");
	}
	public boolean connectToDatabase() throws java.rmi.RemoteException
	{
		System.out.println("Connection to the MYSQL server: " + sysName + "...");
		try
		{
			conn = DriverManager.getConnection("jdbc:mysql:" + "//" + sysName 
					+ "/" + dbName, userId, password);
			Statement stat = conn.createStatement();
			ResultSet rs = stat.executeQuery("SELECT * FROM locations");
			System.out.println("**Query Result**");
			while(rs.next())
			{
				alAddress.add(rs.getString(1));
				alX.add(rs.getDouble(2));
				alY.add(rs.getDouble(3));
			}
			for(int i = 0; i < alAddress.size(); i++)
			{
				System.out.println(alAddress.get(i) + " "
						+ alX.get(i) + " " + alY.get(i));
			}
			rs.close();
			stat.close();
		}
		catch(SQLException exc)
		{
			System.out.println("connection failed with: " + exc.getMessage());
			return false;
		}
		System.out.println("database connection-OK");
		GetClientIP getIp = new GetClientIP();
		return true;
	}
	public boolean disconnectToDatabase() throws java.rmi.RemoteException
	{
		System.out.println("Close the database connection....");
		try
		{
			if(conn != null)
				conn.close();
		}
		catch(SQLException se) {se.printStackTrace(); return false;}
		System.out.println("disconnected from database....");
		alAddress = new ArrayList();
		alX = new ArrayList();
		alY = new ArrayList();
		return true;	
	}
	public boolean add(Location l) throws java.rmi.RemoteException, DuplicatedAddressException
	{
		//boolean flag = true;
		for(int checkDup = 0; checkDup < alAddress.size();checkDup++)
		{
			if(l.getAddress().equals(alAddress.get(checkDup).toString()))
				{
					throw new DuplicatedAddressException( "The address you entered is already inserted" );
					//flag = false;
				}
		}
		alAddress.add(l.getAddress());
		alX.add(l.getX());
		alY.add(l.getY());
		/*for(int i = 0; i < alAddress.size(); i++)
		{
			System.out.println(alAddress.get(i) + " "
					+ alX.get(i) + " " + alY.get(i));
		}*/
		try
		{
			int getSize = alAddress.size();
			Statement stat = conn.createStatement();
			stat.executeUpdate("INSERT INTO locations ( address, coorx, coory )" +
					" VALUES ('" + alAddress.get(getSize-1).toString() + "', '" + Double.parseDouble(alX.get(getSize-1).toString()) + "', '" + Double.parseDouble(alY.get(getSize-1).toString()) + "')");
			alAddress = new ArrayList();
			alX = new ArrayList();
			alY = new ArrayList();
			ResultSet rs = stat.executeQuery("SELECT * FROM locations");
			System.out.println("**Query Result**");
			while(rs.next())
			{
				alAddress.add(rs.getString(1));
				alX.add(rs.getDouble(2));
				alY.add(rs.getDouble(3));
			}
			for(int i = 0; i < alAddress.size(); i++)
			{
				System.out.println(alAddress.get(i) + " "
						+ alX.get(i) + " " + alY.get(i));
			}
			rs.close();
			stat.close();
		}
		catch (SQLException exc)
		{
			System.out.println("query failed with: " + exc.getMessage());
			return false;
		}
		return true;
	}
	
	public Location[] createReport() throws java.rmi.RemoteException
	{
		int locationSize = alAddress.size();
		String tempAddress;
		double tempX;
		double tempY;
		Location[] retLocations = new Location[locationSize];
		for(int i=0;i<locationSize;i++)
		{
			tempAddress = alAddress.get(i).toString();
			tempX = Double.parseDouble(alX.get(i).toString());
			tempY = Double.parseDouble(alY.get(i).toString());
			retLocations[i] = new Location(tempAddress, tempX, tempY);
			//retLocations[i].set(tempAddress, tempX, tempY);
			//retLocations[i].display();
		}
		//System.out.println(locationSize);
		return retLocations;
	}
	
	public class GetClientIP extends Applet 
	{
		  public GetClientIP() 
		  {
			    try 
			    {
				     InetAddress thisIp =
				        InetAddress.getLocalHost();
				     System.out.println("Clients IP: " + thisIp.getHostAddress());
			    }
			    catch(Exception e) 
			    {
			     	e.printStackTrace();
			    }
		   }
	}
}

The DuplicatedAddressException works on the client side (in a try and catch it catches when a duplicate entry is made) but it gives me the errors

java.rmi.UnmarshalException; error unmarshaling retun; nested exception is:
java.lang.ClassNotFoundException: DuplicatedAddressException <no security manager:
RMI class loader disabled>

[gauravfzd]

Use policy file in your application. On both sides i.e. at the server side and at client side.
To create a policy file use the command "policytool" provided with the jdk.

In your code use

if(System.getSecurityManager() == null){
     System.setSecurityManager(new RMISecurityManage());  
}

after that start the program with the following switch:

>java -Djava.security.policy=<PathToPolicyFile> <Your Class having Main method.>