Question

everyone. I have a rookie question about the returning value in java. Here’s my code.

@Override
public long addDrugTreatment(long id, String diagnosis, String drug,
        float dosage) throws PatientNotFoundExn {
    try {
        Patient patient = patientDAO.getPatientByDbId(id);
        long tid = patient.addDrugTreatment(diagnosis, drug, dosage);

        Connection treatmentConn = treatmentConnFactory.createConnection();
        Session session = treatmentConn.createSession(true, Session.AUTO_ACKNOWLEDGE);
        MessageProducer producer = session.createProducer(treatmentTopic);

        TreatmentDto treatment = null;
        ObjectMessage message = session.createObjectMessage();
        message.setObject(treatment);
        producer.send(message);

        return tid;
    } catch (PatientExn e) {
        throw new PatientNotFoundExn(e.toString());
    } catch (JMSException e) {
        logger.severe("JMS Error: " + e);
    }
}

Eclipse reports a “This method must return a result of type long” error. Yet I did return the tid in the try block; eclipse suggests to add a return value after the try/catch block, which would break the logic. Could you please tell me what wrong here? Thanks.

Answer 1

When a JMSException is thrown the return value is undefined. When an exception is thrown, control passes immediately to the exception handler. In this case, you log the error. Then control continues from that point which goes to the end of the function without returning a value. You either need to return a value or throw an exception.