Java remote method invocation
part 4/7 · 10.4 KB total
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Example
The following classes implement a simple client-server program using RMI that displays a message.
RmiServerIntf interface
defines the interface that is used by the client and implemented by the server. This extends the java.rmi.Remote interface, which serves to identify an implementing class as one with remotely-invokable methods.
import java.rmi.Remote;
import java.rmi.RemoteException;
public interface RmiServerIntf extends Remote {
String getMessage() throws RemoteException;
}
RmiServer class
listens to RMI requests and implements the interface which is used by the client to invoke remote methods.
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.registry.*;
public class RmiServer extends UnicastRemoteObject implements RmiServerIntf {
public static final String MESSAGE = "Hello World";
public RmiServer() throws RemoteException {
super(0); // required to avoid the 'rmic' step, see below
}
public String getMessage() {
return MESSAGE;
}
public static void main(String[] args) throws Exception {
System.out.println("RMI server started");
try { //special exception handler for registry creation
LocateRegistry.createRegistry(1099);
System.out.println("java RMI registry created.");
} catch (RemoteException e) {
//do nothing, error means registry already exists
System.out.println("java RMI registry already exists.");
}
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