Cannot get children because it is not a folder.

Hi there,

I am using Tanukisoft JSW service wrapper and I get an exception that says: Cannot get children of wrapper-windows-x86-64.dll because it is not a folder. After debugging it I saw that CommonsVfs2UrlType:83 simply says file.getChildren() and in my case the DLL file is a file, not a folder. So I added an if-statement to check if it's a folder and only then get the children. Now it works perfectly.

Please review and merge.
Also once commons-vfs2 v.2.1 is out there will be a new method FileObject.isFolder() so maybe that will be a better way to check if it's a folder.