This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
this will never work (it's scrollPane.setViewportView(contentPane) - excuse typos)
this is likely to be the problem:
> The JFrame content pane is a simple JPanel with no layout.
the basics of a scrollpane is that the preferredSize of the component in the viewport
must be bigger than the preferredeSize of the scrollpane - i.e. if the panel has no layout,
then it has no preferredSize = you must set it.