java rmi执行的时候遇到的问题，大家帮帮忙？？

[男人不坏cc]

服务器端

package org.ngweb.rmi;

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
/**
 * The implementation class of the remote method defined in interface
 * 
 * @author Huangng
 *
 */
public class Rmi extends UnicastRemoteObject implements RmiInterface {
	private static final long serialVersionUID = 1L;

	// The constructor have to throw RemoteException
	public Rmi() throws RemoteException {
	}

	// The implemented remote method.
	public String say(String name) throws RemoteException {
		System.out.println("Called by HelloClient");
		return "Hello, " + name;
	}
}
package org.ngweb.rmi;

import java.rmi.Remote;
import java.rmi.RemoteException;

/**
 * 
 * An interface that define the remote method, which should be in both server
 * and client end.
 * 
 * @author Huangng
 * 
 */
public interface RmiInterface extends Remote {
	// Any remote method have to throw RemoteException
	public String say(String name) throws RemoteException;
}
package org.ngweb.rmi;

import java.rmi.Naming;
import java.rmi.registry.LocateRegistry;

/**
 * 
 * Java RMI server
 * 
 * @author Huangng
 * 
 */
public class RmiServer {

	public static void main(String[] argv) {
		try {
			// set port number to 1099
			LocateRegistry.createRegistry(1099);

			// The instance of class with remote method
			RmiInterface hello = new Rmi();

			// Register the instance
			Naming.rebind("Hello", hello);

			System.out.println("Starting RMI Server success.");
		} catch (Exception e) {
			System.out.println("Starting RMI Server failed: " + e);
		}
	}
}

//客户端

package org.ngweb.rmi;

import java.rmi.Naming;

/**
 * 
 * A client end of Java RMI
 * 
 * @author Huangng
 * 
 */
public class RmiClient {

	public static void main(String[] argv) {
		try {
			// Find an instance of Hello in remote machine
			RmiInterface hello = (RmiInterface) Naming
					.lookup("//127.0.0.1:1099/Hello");

			// Call remote method
			System.out.println(hello.say("huang"));
		} catch (Exception e) {
			System.out.println("RMI Client exception: " + e);
		}
	}
}
package org.ngweb.rmi;

import java.rmi.Remote;
import java.rmi.RemoteException;

/**
 * 
 * An interface that define the remote method, which should be in both server
 * and client end.
 * 
 * @author Huangng
 * 
 */
public interface RmiInterface extends Remote {
	// Any remote method have to throw RemoteException
	public String say(String name) throws RemoteException;
}

服务器启动后，第二次打开客户端会报错；监听1099端口会发现，会生成两个环路进程造成报错,不知道怎么回事，有的电脑就不会报错。求解。

[男人不坏cc]

[男人不坏cc]

请大家帮忙看看，我是新手，没写过这方面的代码