RestTemplate

   @Autowired

   private RestTemplateBuilder restTemplate;

   public void downloadFile(){     // This method will download file using RestTemplate

       try {

           HttpHeaders headers = new HttpHeaders();

           headers.setAccept(Arrays.asList(MediaType.APPLICATION_OCTET_STREAM));

           HttpEntity<String> entity = new HttpEntity<>(headers);

           ResponseEntity<byte[]> response = restTemplate.build()

                                                         .exchange("http://localhost:8080/downloadFile", HttpMethod.GET, entity, byte[].class);

           Files.write(Paths.get("e:\\download-files\\demo1.pdf"), response.getBody());

       }catch (Exception e){

           e.printStackTrace();

       }

   }