byte[] bpmnBytes = null;

        String filename = null;

        JsonNode editorNode = new ObjectMapper().readTree(repositoryService.getModelEditorSource(modelId));

        BpmnJsonConverter jsonConverter = new BpmnJsonConverter();

        BpmnModel model = jsonConverter.convertToBpmnModel(editorNode);

        filename = model.getMainProcess().getId() + ".bpmn20.xml";

        bpmnBytes = new BpmnXMLConverter().convertToXML(model);

        ByteArrayInputStream in = new ByteArrayInputStream(bpmnBytes);