Template:Json API HMAC Block- Java

   public static void generateHmacHeaders(HttpURLConnection connection) throws Exception
   {
       final SimpleDateFormat d = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss (z)"); // Create the date string
       d.setTimeZone(TimeZone.getTimeZone("GMT"));
       final String timestampString = d.format(new Date());
       final String message = applicationId + ":" + applicationPassword + ":" + timestampString;// Create the message
       final String auth = "HMAC " + hmacSha1ToBase64(message, apiSecret); // Create the authorization hash
       connection.setRequestProperty("updox-timestamp", timestampString);  // Set the request headers
       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");
   }