Try this - works also on Windows
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileOwnerAttributeView;
import java.nio.file.attribute.UserPrincipal;
public class FileOwner {
public static void main(String[] args) throws IOException {
Path path = Paths.get("/tmp");
FileOwnerAttributeView ownerAttributeView = Files.getFileAttributeView(path, FileOwnerAttributeView.class);
UserPrincipal owner = ownerAttributeView.getOwner();
System.out.println("owner: " + owner.getName());
}
}