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

Brian Burkhalter brian.burkhalter at oracle.com
Fri May 19 18:59:59 UTC 2017

Please review at your convenience.


--- 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.



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