A CardPanel is not a Swing container on itself but a JPanel with a CardLayout layout manager, resulting in a "tabbed pane without tabs". You can switch the different cards programmatically like this:
// create a JPanel with CardLayout
JPanel cardPanel = new JPanel(new CardLayout());
// add some components to the panel, the second
// argument is a String which identifies the card
cardPanel.add(component1, "card1");
cardPanel.add(component2, "card2");
cardPanel.add(component3, "card3");
// display an arbitrary card, the second argument
// to show() is the identifier
((CardLayout)cardPanel.getLayout()).show(cardPanel, "card2");

There are dialogs for editing the CardLayout's constraints and for rearranging cards.

You can also define a controller component for a card panel. Every JComboBox, JList or JTree whose number of items (rows) match the number of cards, can be a controller. Select 'Define Controller' from the card panel's context menu. In the 'Define Controller' dialog you can select an appropriate controller and map controller items to cards.
Context menu 'Define Controller' dialog
Note: It is possible to control several card panels with one controller. See example layout 26 Eclipse Project Properties where the tree at the left controls the card panel.

To select another card, to remove a card, to rearrange cards or to edit the constraints (identifiers), select the according menu item from the card panel's context menu.
CardPanel's context menu

Note: You can switch from CardPanel to JTabbedPane and vice versa at every time without affecting the number or order of child components.