serviceRemoved / serviceAdded problem

Hi all again,

 

I have an application running a number x of Jini services (according to configuration x can be over than 10 in a specific production environment). 

For now all the services run in a single machine (RedHat9.0 jsdk5).

I'm using Jini 2.1.

I use the http server provided in classserver.jar. I also use reggie, norm, and fiddler services.

 

Some services act as client of other services.

Each service acting as a client, has a lookup cache to the services it uses more frequently:

            ...

discover = new LookupDiscoveryManager(groups, locators, null);

      sdm = new ServiceDiscoveryManager(discover, new LeaseRenewalManager(), conf);

      

      serviceTemplate = new ServiceTemplate (null,

                                             new Class[] {IServiceX.class},

                                             new Entry[] {entry});

 

lCache = sdm.createLookupCache(serviceTemplate, null, new ServiceListener());

...

In this case a service say ClientService uses a lookupCache for the service x (IServiceX).

 

The application runs with no problem for while. Sometimes it takes 5 or more days until the problem occurs...

 

THE PROBLEM:

 

At a given point in time, I don't know why, the client services receive through their implementation of ServiceListener(), the notifications of

serviceRemoved and then serviceAdded for all the services it is a client (all the services in the LookupCache). 

 

The application recovers a few minutes later because there is a corresponding serviceAdded  few moments after a serviceRemoved notification is sent, 

but until it recovers the application doesn't respond which is expected according to what's happening. 

Note: with Jini 2.0_2 I had the same problem, but sometimes some client services only received a serviceRemoved notification and no corresponding serviceAdded. That would crash my application.

Changing to Jini 2.1 corrected the problem of not receiving the corresponding serviceAdded... but the question remains:

 

QUESTION:

What causes this serviceRemoved / serviceAdded sequence? 

 

Could be service lease expiration?

I'm trying get a cpu analyser to see if the cpu has some peeks. Could this be associated? I wonder if in a peek of cpu it can't renew services (???)

 

But I'm a little bit confused because net.jini.lookup.ServiceDiscoveryManager.registerListener() does this:

 

leaseRenewalMgr.renewFor(eventLease,

                         duration, //equals to LONG.MAX_VALUE

                         new LeaseListenerImpl(proxy));

 
and according to api doc this is the same as 
 
renewFor(eventLease, duration, Lease.FOREVER, new LeaseListenerImpl(proxy));
 
so this means that the lease will last LONG.MAX_VALUE and will never need to be renewed (because renewal duration = Lease.FOREVER) right?
So it can't be a renewal problem...

 

 

What else could it be?

 

 

 

Thanx in advance for any help

Best regards

Francisco Mourão

 

 


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