code: public Instant getInstant(String key) {
  		String s = get(key);
  		if (s != null) {
  			try {
  				return Instant.ofEpochMilli(Long.parseLong(s));
  			}
  			catch (NumberFormatException ex) {
  				// Not valid epoch time
  			}
  		}
  		return null;
  	}
docs: Return the value of the specified property as an {@link Instant} or {@code null} if
  the value is not a valid {@link Long} representation of an epoch time.
  @param key the key of the property
  @return the property value