FileObject src = fsManager.resolveFile(from);
FileSystem fs = null;
FileSystemManager fsmnull;

<-- In processing(), do your things, including src = children[0] -->

public void release() {
    FileSystem fs = null;

<-- do your things -->

 this.src.close(); // Seems to still work even if this line is omitted
    fs = this.src.getFileSystem(); // This works even after the src is closed.
fsm   = fs.getFileSystemManager();
fsmthis.fsManager.closeFileSystem(fs);
}