Connecting to java RMI server

Question

I am new to java RMI, i was following a tutorial to learn about it. It uses a server, the code listing is as below for getting to the server

1. CalculatorServer.java

    public class CalculatorServer {
           public CalculatorServer(){
               try {
                   Calculator c = new CalculatorImpl();
                   Naming.rebind("rmi://localhost:1099/CalculatorService", c);
               } catch (Exception e) {
                   System.out.println("Trouble"+e);
               }
           }
           public static void main(String args[]){
               new CalculatorServer();
           }
       }
   

2. CalculatorImpl.java

    public class CalculatorImpl extends UnicastRemoteObject implements Calculator {
   
       //constructor
       public CalculatorImpl() throws RemoteException {
           super();
       }
   
       //@Override
       public long add(long a, long b) throws RemoteException {
           return a + b;
       }
   
       //@Override
       public long sub(long a, long b) throws RemoteException {
           return a - b;
       }
   
       //@Override
       public long mul(long a, long b) throws RemoteException {
           return a * b;
       }
   
      // @Override
       public long div(long a, long b) throws RemoteException {
           return a / b;
       }
   }
   

3.Calculator.java

  public interface Calculator extends Remote{
    public long add(long a, long b) throws RemoteException;
    public long sub(long a, long b) throws RemoteException;
    public long mul(long a, long b) throws RemoteException;
    public long div(long a, long b) throws RemoteException;
  }

When i debug the program, here is the error by netbeans ide console; it says this error : Troublejava.rmi.ServerException: RemoteException occurred in server thread; nested exception is: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: java.lang.ClassNotFoundException: rmi.Calculator

Answer 1

It sounds like you are not running the RMI registry, which is a separate process from your CalculatorServer program. It is be located in your java bin directory. Give it a moment to start up, then try your code again.