checking object deletion

Hi,

I'm writing a Java CORBA client, and am using the following code to
check if a pair of remote object references are still valid:

try {

    if (workOrderInterface._non_existent() ||
eventFilterInterface._non_existent()) {
        doSessionRefresh();
    }
} catch (RuntimeException rex) {

    //
    // The _non_existent() calls above may have been throwing
NullPointerExceptions
    // This handler should ensure that if anything unexpected happens,
we'll forcibly
    // refresh the session
    //
    LOG.error("Error checking session validity. Session will be
forcibly refreshed", rex);
    doSessionRefresh();
}

I added the try-catch, because _non_existent() was throwing a
NullPointerException. The evidence was provided by the following stack
trace I found in my logs:

Caused by: java.lang.NullPointerException
 at com.inprise.vbroker.orb.ORB.getThreadLocalObject(Unknown Source)
 at com.inprise.vbroker.qos.PolicyHelper.get_client_policy(Unknown
Source)
 at com.inprise.vbroker.orb.DelegateImpl.get_policy(Unknown Source)
 at org.omg.CORBA.portable.ObjectImpl._get_policy(ObjectImpl.java:310)
 at com.inprise.vbroker.GIOP.ProtocolConnector.doServiceContext(Unknown
Source)
 at com.inprise.vbroker.GIOP.ProtocolConnector.doServiceContext(Unknown
Source)
 at com.inprise.vbroker.IIOP.ProtocolConnector.doServiceContext(Unknown
Source)
 at com.inprise.vbroker.GIOP.ProtocolConnector.request(Unknown Source)
 at com.inprise.vbroker.GIOP.ProtocolConnector.pseudoRequest(Unknown
Source)
 at com.inprise.vbroker.GIOP.ProtocolConnector.non_existent(Unknown
Source)
 at com.inprise.vbroker.orb.DelegateImpl.non_existent(Unknown Source)
 at
org.omg.CORBA.portable.ObjectImpl._non_existent(ObjectImpl.java:137)
 at
com.acecomm.parentpatrol.surePay.SurePaySession.refreshSessionIfNecessary(SurePaySession.java:335)

Anyway, my question is this.....is there a better way to check whether
a remote object reference is still valid? Preferably, one which doesn't
throw any runtime exceptions :)
 
Thanks in Advance,
DM