Java Open Files on Windows/NTFS - not closing

Problem: Java App with embedded database. On Linux/Mac closing the database also closes all the open files. On Windows, I find that the database will stop cleanly but the files it is using are held open by the JVM. ( proc explorer lists them, can't delete or rename them)

I am guessing the difference between the behavior on Windows and *ix is down to how the JVM interacts with NTFS.

any suggestions on how to do one of the following:

1. Close a file that was opened by a thread which has now terminated?


2. Change NTFS settings or JVm property to ensure the closure?

Also open to other debug ideas: jstack -l, visualvm, process explorer and running in IDE with break points to introduce pauses etc. have not helped other than to further my Java education on Windows.

Thanks, FITCS