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Message:

I am so frustrated!!! Please help!

Posted by Peter Schramm on August 13, 2001 at 5:32 AM

Do you have a webserver running that exports your jini service proxy? It is just the effect that there is no service instance if the lookup service cannot download it from the jini service.

If you use a dummy object like String it does not need to be downloaded. I think the lookup service simply creates one on his own...

Greetings, Peter

> I am so frustrated!!! Please help!

> These are part of my code:
> ----------------------------------
> public class FortuneStreamStart implements ServiceIDListener
> {
> public static void main(String[] args) throws Exception
> {
> new FortuneStreamStart();

> Object keepAlive = new Object();
> synchronized(keepAlive) {
> try {
> keepAlive.wait();
> } catch(InterruptedException e) { }
> }
> }

> public FortuneStreamStart(String[] args)
> {
> System.setSecurityManager(new RMISecurityManager());

> String[] groups = new String[] { "" };
> LookupDiscoveryManager lookupDisc =
> new LookupDiscoveryManager(groups, null, null);

> JoinManager joinMgr =
> new JoinManager(new FortuneStreamImpl(),
> null, this,
> lookupDisc, null);
> }

> public void serviceIDNotify(ServiceID serviceID)
> {
> System.out.println(serviceID);
> }
> }
> .....
> public class FortuneStreamImpl
> extends UnicastRemoteObject
> implements java.io.Serializable
> {
> public FortuneStreamImpl()
> throws IOException, RemoteException
> {
> super();
> }

> public String toString()
> {
> return "jianbo";
> }
> }
> ----------------------------------
> It is quite simple, right? Well, here is the problem:
> After I started it, I got the ServiceID: 6bc8a1c8-6a5a-44eb-99ff-e43732177ebb. Then, I used Jini's Browser to look it up. The Browser showed these:
> ================================================
> Matching services: 2

> Service ID: 6bc8a1c8-6a5a-44eb-99ff-e43732177ebb
> Service instance: null

> Service ID: bcf362b3-6b22-4fc1-985d-cf054279e3d9
> Service instance: com.sun.jini.reggie.RegistrarProxy@df501ae
> ServiceInfo: name=Lookup manufacturer=Sun Microsystems, Inc. vendor=Sun Microsystems, Inc. version=1.1 model= serialNumber=
> BasicServiceType: type=Lookup
> ================================================
> I don't understand why my Service instance is null, so I changed JoinManager() line in my cold to:

> JoinManager joinMgr =
> new JoinManager(new String("Test"),
> null, this,
> lookupDisc, null);

> Then, the Browser showed these:
> ================================================
> Matching services: 3

> Service ID: 09f196e4-b6ff-45ef-ac6c-d8fb0f214ac3
> Service instance: Test

> Service ID: 6bc8a1c8-6a5a-44eb-99ff-e43732177ebb
> Service instance: null

> Service ID: bcf362b3-6b22-4fc1-985d-cf054279e3d9
> Service instance: com.sun.jini.reggie.RegistrarProxy@df501ae
> ServiceInfo: name=Lookup manufacturer=Sun Microsystems, Inc. vendor=Sun Microsystems, Inc. version=1.1 model= serialNumber=
> BasicServiceType: type=Lookup
> ================================================

> You see: The Service instance is "Test" now.
> Why my Service instace is null? Why "new String()" works but my "new FortuneStreamImpl()" doesn't? I have tried so many things I can think of, but I simply cannot fix it. Please tell me what I did wrong.
> Thanks a lot.

> (I am using Jini1_1 and JDK1.3.)