code: public static String getHash(final String password, final String salt) {
  
  		if (StringUtils.isEmpty(salt)) {
  
  			return getSimpleHash(password);
  
  		}
  
  		return DigestUtils.sha512Hex(DigestUtils.sha512Hex(password).concat(salt));
  
  	}
docs: Calculate a SHA-512 hash of the given password string.
  
  If salt is given, use salt.
  
  @param password
  @param salt
  @return hash