Remote HashMap

Question

I have a server object pusblishing one member of type HashMap, and clients getting
a reference to it in order to modify its contents. Something like :
class Server {
HashMap map ;
public HashMap getMap(){
return map;
on the client :
HashMap map = server.getMap();
map.put(key,val);
Everything goes right, except that the map object on the server is never modified.
I tried to extend HashMap to have it implement Remote and to export if with
UnicastRemoteObject staticmethod, but on the client side it's no more an HashMap.
How can i reference the HashMap or a Vector too over the network?
Thanks.

Answer 1

When you are using the HashMap remotely, you are actually working on a copy. There's really no such thing as 'pass by reference' in RMI (I don't believe). After you modify the HashMap, you will have to synchronize/update the server's original copy of the HashMap. You will have to write this logic yourself. The best advice I could give is to find a way to get a callback working on the server that's like onChangeEvent or something to that effect, so it can update the main HashMap there on the server.