import javax.sip.*; import javax.sip.message.*; import javax.sip.address.*; import javax.sip.header.*; SipFactory sipFactory = SipFactory.getInstance(); sipFactory.setPathName("gov.nist"); SipStack sipStack = sipFactory.createSipStack(properties); ListeningPoint lp = sipStack.createListeningPoint(host, port, transport); SipProvider sipProvider = sipStack.createSipProvider(lp); class SipListenerImpl implements SipListener { } sipProvider.addSipListener(sipListener); Request registerRequest = messageFactory.createRequest(requestURI, "REGISTER", callIdHeader, cSeqHeader, fromHeader, toHeader, viaHeaders, maxForwardsHeader); ClientTransaction transaction = sipProvider.getNewClientTransaction(registerRequest); transaction.sendRequest(); public void processResponse(ResponseEvent responseEvent) { Response response = responseEvent.getResponse(); }