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{

   // Get an hmac_sha1 key from the raw key bytes
   byte[] keyBytes = key.getBytes();
   SecretKeySpec signingKey = new SecretKeySpec(keyBytes, "HmacSHA1");

   // Get an hmac_sha1 Mac instance and initialize with the signing key
   Mac mac = Mac.getInstance("HmacSHA1");
   mac.init(signingKey);

   // Compute the hmac on input data bytes
   byte[] rawHmac = mac.doFinal(value.getBytes());

   // Convert raw bytes to Hex
   byte[] base64Bytes = Base64.encodeBase64(rawHmac);

   // Covert array of Hex bytes to a String
   return new String(base64Bytes, "UTF-8");

}