Swing provides a rich set of components that can be used to create graphical user interfaces (GUIs) for desktop applications. Some of the most commonly used Swing components in Java include:

1. JLabel - Displays a single line of read-only text or an image.

2. JTextField - Allows the user to enter a single line of text.

3. JTextArea - Allows the user to enter multiple lines of text.

4. JCheckBox - Allows the user to select one or more options from a list.

5. JRadioButton - Allows the user to select one option from a list.

6. JComboBox - Displays a drop-down list of items that the user can select.

7. JList - Displays a list of items that the user can select.

8. JTable - Displays a grid of data that the user can edit.

9. JScrollPane - Provides a scrollable view of a component that is larger than the visible area.

10. JToolBar - Displays a bar of buttons and other controls that the user can click.

11. JMenuBar - Displays a menu bar with menus that the user can select.

12. JPopupMenu - Displays a pop-up menu that the user can select.

13. JButton - Provides a clickable button that performs an action.

14. JDialog - Provides a modal or non-modal dialog box for displaying information or getting input from the user.

15. JFrame - Provides the main window for a desktop application.

Swing components can be customized in a variety of ways, such as by changing their appearance, behavior, and layout. Developers can use layout managers to position components on a container, and can apply different look-and-feel styles to change the appearance of the GUI. With Swing, developers can create rich, interactive, and responsive desktop applications that are both powerful and easy to use.