[SNMP4J] snmp.inform question

[Wayne T]

The javadoc states the following for SNMP.inform(...)
Returns:the received response encapsulated in a ResponseEvent
    instance. To obtain the received response PDU call
    ResponseEvent.getResponse(). If the request timed out,
    that method will return null.
Throws:
java.io.IOException - if the inform request could not be send to the specified target.
The
 snmp.inform command always seems to return a resposeEvent with 
responseEvent.getResponse() == null.  It doesn't matter if I send to a 
IP Address that does not exist in the network, or on a port that is not 
listened on.  It also does not throw IOException.  

In fact, when
 I send an inform PDU using SnmpRequest with args "-v 2c -p INFORM", the
 following code is called but the response is always set to null.
      long startTime = System.nanoTime();
      responseEvent = snmp.send(request, target);
      if (responseEvent != null) {
        response = responseEvent.getResponse();
        System.out.println("Received response after "+
                           (System.nanoTime()-startTime)/1000000+" milliseconds");
      }


In what case does inform throw an IOException?

Is there something that needs to be initialized so that responseEvent.getResponse() will return something other than null?

Thanks,

Wayne.