RMI没有这样的对象异常

我试图从Oracle页面运行Hello World RMI示例，但是我一直遇到错误。

我不断得到的错误是

服务器异常：java.rmi.NoSuchObjectException：表中没有这样的对象java.rmi.NoSuchObjectException：sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer（StreamRemoteCall.java:275）处的表中没有这样的对象.executeCall（StreamRemoteCall.java:252）在sun.rmi.server.UnicastRef.invoke（UnicastRef.java:378）在sun.rmi.registry.RegistryImpl_Stub.bind（未知源）在example.hello.Server.main（Server） .java：26）

这是直接从我使用的站点获取的代码：

Hello界面：

包example.hello;

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

public interface Hello extends Remote {
    String sayHello() throws RemoteException;
}

这是我的服务器类：

package example.hello;

import java.rmi.registry.Registry;
import java.rmi.registry.LocateRegistry;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;

public class Server implements Hello {

    public Server() {}

    public String sayHello() {
        return "Hello, world!";
    }

    public static void main(String args[]) {

    try {
        Server obj = new Server();
        Hello stub = (Hello) UnicastRemoteObject.exportObject(obj,0);

        // Bind the remote object's stub in the registry
        Registry registry = LocateRegistry.getRegistry("localhost");
        registry.bind("Hello", stub);

        System.err.println("Server ready");
        } catch (Exception e) {
            System.err.println("Server exception: " + e.toString());
            e.printStackTrace();
        }
    }
}

客户代码：

package example.hello;

import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

public class Client {

    private Client() {}

    public static void main(String[] args) {

        String host = "localhost";
        try {
            Registry registry = LocateRegistry.getRegistry(host);
            Hello stub = (Hello) registry.lookup("Hello");
            String response = stub.sayHello();
            System.out.println("response: " + response);
        } catch (Exception e) {
            System.err.println("Client exception: " + e.toString());
            e.printStackTrace();
        }
    }
}

任何反馈，我们将不胜感激！