RMI and Threading: Urgent, pls help!

Question

Hi everyone,
I read the previous topics in multithreading but i'm still confused about how RMI works in this case.
I have a client server application with RMI where client runs some time-consuming executables on the server.
(i use Process proc = Runtime.getRuntime().exec(cmd...)...)
Basically I want to make sure that simultaneous requests from different clients execute concurrently, instead of waiting for each other to finish. So my questions are:
1) When mutiple clients are making remote calls, does RMI map each client request to separate thread and execute them simultaneously (if yes, does it have some limit on number of threads that can be created?);
Or will I have to take care of creating threads on the server side for each request myself? if the later is the case, how could I go about doing that?
2) What if all (or some of) the clients are connected from the same VM? How can I ensure that they get executed in different threads, concurrently. Could you pls direct me to ways of implementing it.
any help is greatly appreciated,
yulduz

Answer 1

1) When mutiple clients are making remote calls, does RMI map each client request to separate
thread and execute them simultaneously (if yes, does it have some limit on number of threads
that can be created?); Yes, RMI takes care of launching a thread on each remote call. It actually maintains a pool of threads from which, a free thread is assigned a new request. From then on, you have different threads running in server VM (one per each client call).
Or will I have to take care of creating threads on the server side for each request myself? if the
later is the case, how could I go about doing that?No, you dont have to create any thread just for the purpose of handling a remote call.
2) What if all (or some of) the clients are connected from the same VM? How can I ensure that
they get executed in different threads, concurrently. Could you pls direct me to ways of
implementing it.You dont have to do anything extra for achieving this. It doesnt matter whether you are running clients in the same VM or different VMs. If you want concurrency on the client side, you have to make remote calls from different threads. The following code outlines the difference between concurrency and non-concurrency in client VM (and NOT server VM).
class CallerThread extends Thread {
     public void run() {
          remoteRef.callMethod();
public class Client {
    ... main() {
        // these are not concurrent in client VM bcos the second call happens only after first one       returns
        remoteRef.callMethod1();        
        remoteRef.callMethod2();
        CallerThread t1, t2;
        // these two calls are concurrent on the client side as they're called from two different threads
        t1.start();        
        t2.start();
}regds,
CA