public static String convertToReadableTime(Long timestamp) {
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    return dateFormat.format(new Date(timestamp));
  }
Milliseconds to readable format in current server timezone
@param timestamp
@return
ambari-server/src/main/java/org/apache/ambari/server/utils/DateUtils.java