[SNMP4J] snmp get returns null

[Mark Moorcroft]

I've been trying to query a Motorola device but am not having much  
luck.  I wrote a small test application to send a get request and read  
the response but the response object is null.  I ran a tcpdump and can  
see both the request and response messages over the wire.  Thus it has  
something to do with the way the code is listening for the packets.  I  
followed the suggestions in the javadocs and invoke snmp.listen()  
before I call the get method.  The code looks something like the  
following:

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		LogFactory.setLogFactory(new Log4jLogFactory());

		String community = "opennms-Priv";
		String address = "xx.xx.xx.xx/161";   // <<< hide the IP address
		String strOID = "1.3.6.1.4.1.161.19.3.1.4.1.26.3";

		
		CommunityTarget target = new CommunityTarget();
		target.setCommunity(new OctetString(community));
		Address targetAddress = new UdpAddress(address);
		target.setAddress(targetAddress);
		target.setVersion(SnmpConstants.version2c);
		target.setRetries(0);
		target.setTimeout(4000);

		TransportMapping transport = new DefaultUdpTransportMapping();
		Snmp snmp = new Snmp(transport);
		snmp.listen();

		
		PDU pdu = new PDU();
		pdu.add(new VariableBinding(new OID(strOID)));
		pdu.setType(PDU.GET);

		ResponseEvent response = snmp.get(pdu, target);

		if (response.getResponse() == null) {
			// request timed out
			System.out.println("request timed out!");

		} else {
			System.out.println("Received response from: "
					+ response.getPeerAddress());
			// dump response PDU
			System.out.println(response.getResponse().toString());
		}
		snmp.close();
	}

I'm debugging the code from within Eclipse 3.4.1 using JDK 1.5 on  
MacOS X Leopard.  Thanks for any help you may provide.

Cheers,
Mark