There's no built-in functionality to do that.  You'll simply have to
poll the files that you want to watch.  Use a java.util.Timer to check
the file(s) every second or so.  Something like:

class WatchFile {
 File file;
 Timer timer = new Timer();

 WatchFile(File file) {
   this.file = file;
   timer.schedule(new TimerTask() { public void run() { check(); } },
0, 1000);
 }
 long lastModified;
 private void check() {
   long l = file.lastModified();
   if (l != lastModified) {
     lastModified = l;
     fireFileChanged();
   }
 }

 protected void fireFileChanged() {
   //....
 }
}

Hope this helps,

Walter
----
Walter Gildersleeve
Freiburg, Germany

"In science, 'fact' can only mean 'confirmed to such a degree that it
would be perverse to withhold provisional assent.' I suppose that
apples might start to rise tomorrow, but the possibility does not merit
equal time in physics classrooms." -- Stephen Jay Gould

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No, there are not.  You would need to write a background thread that
polls the directory listing and generates the event.

No, as such behavior is very OS specific.
Of cause, you could use JNI to run some native code, but that will limit you
to one platform.

Alun Harford