JDK 9 doc-api-only RFR of 6791812: (file spec) Incompatible File.lastModified() and setLastModified() for negative time

[Roger Riggs]

Hi Brian,

That looks ok.

The ambiguity (of zero) can't easily be resolved, but I would be inclined,
if the file exists and was created exactly at the epoch to bump the 
create time by 1.

Roger


On 5/19/2017 2:59 PM, Brian Burkhalter wrote:
> Please review at your convenience.
>
> https://bugs.openjdk.java.net/browse/JDK-6791812
>
> --- a/src/java.base/share/classes/java/io/File.java
> +++ b/src/java.base/share/classes/java/io/File.java
> @@ -932,7 +932,9 @@
>        * @return  A <code>long</code> value representing the time the file was
>        *          last modified, measured in milliseconds since the epoch
>        *          (00:00:00 GMT, January 1, 1970), or <code>0L</code> if the
> -     *          file does not exist or if an I/O error occurs
> +     *          file does not exist or if an I/O error occurs; the value may
> +     *          be negative in which case its absolute value indicates the
> +     *          number of milliseconds before the epoch
>        *
>        * @throws  SecurityException
>        *          If a security manager exists and its {@link
>
> The weird thing here is that if this method were invoked on a file last modified at 00:00:00 GMT, January 1, 1970, then we would not know whether the file does not exist or whether its last-modified time is the epoch. It seems to me that if the file does not exist it would be better to throw a FileNotFoundException but that is not an issue for JDK 9 at this stage of game.
>
> Thanks,
>
> Brian