You can get information about the files in a directory with
java.io.File. There are various approaches you could use to solve your
problem. Are you using Windows or UNIX?

As klynn47 pointed out you can use java.io.File operations to monitor the
contents of a directory.  However, you should know that there is no real way
to know that a file has been fully added to a directory.  If a 100 MB file
is being added, the file will appear with some part (but not necessarily
all) of its contents.  The file size will grow until the file is fully
present.  Unless you know the size in advance you need to be willing to
guess that copying is finished when the size stops changing. If you have
control over the program that is adding the file, an effective technique is
to get that program to write the file to a temp file first and when the
writing is complete to rename it to the final name.  Renaming a file is
typically an atomic operation whereas copying is not.

Cheers,
Matt Humphrey  matth@ivizNOSPAM.com  http://www.iviz.com/