public String getAccessToken() throws JsonProcessingException {
        String tokenUrl = "https://secure.snd.payu.com/pl/standard/user/oauth/authorize?grant_type=client_credentials&" + "client_id="
                + CLIENT_ID + "&client_secret="+CLIENT_SECRET;

        RestTemplate client = new RestTemplate();
        ResponseEntity<String> response = client.getForEntity(tokenUrl,String.class);
        ObjectMapper mapper = new ObjectMapper();
        JsonNode root = mapper.readTree(response.getBody());
        return root.get("access_token").asText();
    }