Template:Json API HMAC Block- Java

   public static void generateHmacHeaders(HttpURLConnection connection) throws Exception{
        // Create the date string
       final SimpleDateFormat d = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss (z)");
       d.setTimeZone(TimeZone.getTimeZone("GMT"));
       final String timestampString = d.format(new Date());

// Create the message

       final String message = applicationId + ":" + applicationPassword + ":" + timestampString;

// Create the authorization hash

       final String auth = "HMAC " + hmacSha1ToBase64(message, apiSecret); 

// Set the request headers

       connection.setRequestProperty("updox-timestamp", timestampString);  
       connection.setRequestProperty("Authorization", auth);
   }
   
   public static String hmacSha1ToBase64(String value, String key) throws Exception{
       byte[] keyBytes = key.getBytes();
       SecretKeySpec signingKey = new SecretKeySpec(keyBytes, "HmacSHA1");
       Mac mac = Mac.getInstance("HmacSHA1");
       mac.init(signingKey);
       byte[] rawHmac = mac.doFinal(value.getBytes());
       byte[] base64Bytes = Base64.encodeBase64(rawHmac);
       return new String(base64Bytes, "UTF-8");
   }