#vulnerable code 
                                @Override
    protected void doSoService(ServiceDataFlowEvent event, DataFlowContext context, JSONObject reqJson) {

        JSONObject outParam = null;
        ResponseEntity<String> responseEntity = null;
        Map<String, String> reqHeader = context.getRequestHeaders();
        String communityId = reqHeader.get("communityId");
        String machineCode = reqHeader.get("machinecode");
        HttpHeaders headers = new HttpHeaders();
        for (String key : reqHeader.keySet()) {
            if (key.toLowerCase().equals("content-length")) {
                continue;
            }
            headers.add(key, reqHeader.get(key));
        }
        //根据设备编码查询 设备信息
        MachineDto machineDto = new MachineDto();
        machineDto.setMachineCode(machineCode);
        machineDto.setCommunityId(communityId);
        List<MachineDto> machineDtos = machineInnerServiceSMOImpl.queryMachines(machineDto);
        if (machineDtos == null || machineDtos.size() < 1) {
            outParam.put("code", -1);
            outParam.put("message", "该设备【" + machineCode + "】未在该小区【" + communityId + "】注册");
            responseEntity = new ResponseEntity<>(outParam.toJSONString(), headers, HttpStatus.OK);
            context.setResponseEntity(responseEntity);
            return;
        }
        //设备方向
        String direction = machineDtos.get(0).getDirection();

        //进入
        if (MACHINE_DIRECTION_IN.equals(direction)) {
            dealCarIn(event, context, reqJson, machineDtos.get(0), communityId);
        } else {
            dealCarOut(event, context, reqJson, machineDtos.get(0), communityId);
        }
    } 
                            #location 22 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    protected void doSoService(ServiceDataFlowEvent event, DataFlowContext context, JSONObject reqJson) {

        //JSONObject outParam = null;
        ResponseEntity<String> responseEntity = null;
        Map<String, String> reqHeader = context.getRequestHeaders();
        String communityId = reqHeader.get("communityId");
        String machineCode = reqHeader.get("machinecode");
        HttpHeaders headers = new HttpHeaders();
        for (String key : reqHeader.keySet()) {
            if (key.toLowerCase().equals("content-length")) {
                continue;
            }
            headers.add(key, reqHeader.get(key));
        }
        //根据设备编码查询 设备信息
        MachineDto machineDto = new MachineDto();
        machineDto.setMachineCode(machineCode);
        machineDto.setCommunityId(communityId);
        List<MachineDto> machineDtos = machineInnerServiceSMOImpl.queryMachines(machineDto);
        if (machineDtos == null || machineDtos.size() < 1) {
            responseEntity = MachineResDataVo.getResData(MachineResDataVo.CODE_ERROR,"该设备【" + machineCode + "】未在该小区【" + communityId + "】注册");
            context.setResponseEntity(responseEntity);
            return;
        }
        //设备方向
        String direction = machineDtos.get(0).getDirection();

        //进入
        if (MACHINE_DIRECTION_IN.equals(direction)) {
            dealCarIn(event, context, reqJson, machineDtos.get(0), communityId);
        } else {
            dealCarOut(event, context, reqJson, machineDtos.get(0), communityId);
        }
    }