title: How to call the OS functionality to copy over files to a folder?
body: <p>I a Java app, I need to synchronize the contents of two user-selected directories, Source and Target(simple local machine app, no need to consider any filesystem or server stuff and whatnot). The app should copy any new and changed files from Source to the Target and delete any files that are not in the Source but are in the Target. The synchronization process needs to display a progress bar and be cancelable. </p>
  
  <p>The deleting part I guess I'll have to write entirely, but the other behavior is the same as the OS functionality to copy over files from one directory to another, so I could save myself a lot of work by using the functionality that is already there. The problem is, I have no idea how to access it from Java.</p>
  
  <p>So, how do I make Java do the same thing that happens on most OSs if you select some files and drag them onto a folder icon?</p>