Clean way to stop RMI server

Question

A RMI server which works fine without the stopServer functionality.

public class HelloServer extends UnicastRemoteObject implements HelloInterface
{
    priv         


        

Answer 1

You need to store the result of LocateRegistry.createRegistry(), and unexport that. At present you're trying to unexport a stub.

Answer 2

I implemented a shutdown-service in my rmi-server. If I want to shut it down, I call it with a password. Simple Example:

public interface ShutdownInterface extends Remote {
  public void shutdownService(String password) throws RemoteException;
}

The serverside implementation can look something like:

public class ShutdownService extends UnicastRemoteObject implements ShutdownInterface {

private static final long serialVersionUID = 1L;

private boolean doShutdown = false;

public ShutdownService() throws RemoteException {
    super();
}

@Override
public void shutdownService(String password) throws RemoteException {
    if ("abcde12345".equals(password)) {
        System.out.println("shutdown requested.");
        this.doShutdown = true;
    } else {
        System.out.println("wrong pwd for shutdown");
    }

}

public boolean isDoShutdown() {
    return this.doShutdown;
}

}

Now the server itself keeps a reference to this:

public class BackendServer {
public final static int RMI_PORT = 1974;
private Registry registry = null;
private ShutdownService shutdownService = null;

public BackendServer() throws RemoteException {
    registry = LocateRegistry.createRegistry(RMI_PORT);
    this.shutdownService = new ShutdownService();
}

public void initialize() throws AccessException, RemoteException, AlreadyBoundException {
    shutdownService = new ShutdownService();
    registry.bind("ShutdownService", shutdownService);
    registry.bind("MyDataService", new MyDataService());
}

public void stop() throws NoSuchObjectException {
    System.out.println("stopping rmi server.");
    UnicastRemoteObject.unexportObject(registry, true);
    System.exit(0);
}

public boolean shouldStop() {
    return this.shutdownService.isDoShutdown();
}

public static void main(String args[]) {
    try {
        BackendServer bs = new BackendServer();
        bs.initialize();
        System.out.println("Server ready.");

        while (!bs.shouldStop()) {
            Thread.sleep(1000);
        }
        bs.stop();
    } catch (Exception e) {
        System.err.println("Server exception: " + e.toString());
        e.printStackTrace();
    }
}

}

Of course, this can be realized in a more beautiful way, but this should give you an idea of how to easily implement a shutdown yourself. You can call it from the main client or from a small commandline-tool you code for your server.