public void run(String xmlFile, String context) throws JAXBException, FileNotFoundException { Patients patients = new Patients(); List<Patient> patientList = patients.getPatient(); Patient p = new Patient(); p.setId(BigInteger.valueOf(1)); p.setName("John Doe"); p.setDiagnosis("Schizophrenia"); patientList.add(p); JAXBContext jc = JAXBContext.newInstance(context); Marshaller m = jc.createMarshaller(); m.marshal(patients, new FileOutputStream(xmlFile)); }