code: public byte[] sendQuerySm(OutputStream os, int sequenceNumber,
              String messageId, TypeOfNumber sourceAddrTon,
              NumberingPlanIndicator sourceAddrNpi, String sourceAddr)
              throws PDUStringException, IOException {
          synchronized (os) {
              return pduSender.sendQuerySm(os, sequenceNumber, messageId,
                      sourceAddrTon, sourceAddrNpi, sourceAddr);
          }
      }
docs: /*
  (non-Javadoc)
  
  @see org.jsmpp.PDUSender#sendQuerySm(java.io.OutputStream, int,
  java.lang.String, org.jsmpp.TypeOfNumber,
  org.jsmpp.NumberingPlanIndicator, java.lang.String)