So how do you changed the default java swing scrollbar with windows style ?
Image
(Metro style I think ?)
Have you tried
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
in your main() ?
If that is not the Look and feel you want, maybe give this a read: https://docs.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html