GUI Frames and Swing

This lesson introduces graphical user interface (GUI) programming in Java using Swing. It covers frames, common GUI components, layouts, event handling, lists, combo boxes, panels, and menus.

A GUI component is an on-screen object that users interact with through the mouse, keyboard, or another input device.

Common Swing components:

Swing classes are found mainly in javax.swing. Many Swing components are lightweight, meaning they are drawn and managed mostly by Java rather than relying completely on the operating system's native widgets.

Swing GUI classes build on Java's class hierarchy. For example, JFrame is a window, and many components inherit shared behavior from classes such as Component and Container.

A JFrame is a top-level window. Common frame tasks include setting the title, size, layout, close operation, and visibility.

JLabel displays text or icons. JTextField lets the user type a single line of text.

A JButton can respond to clicks using an ActionListener. The listener's actionPerformed() method runs when the button is clicked.

A JCheckBox lets users choose independent options. A JRadioButton is usually placed in a ButtonGroup so only one option in the group can be selected at a time.

JComboBox is useful for choosing one item from a drop-down list. JList displays several items at once and can allow single or multiple selections.

A layout manager controls how components are placed inside a container.

Common layout managers:

Swing menus are built with JMenuBar, JMenu, and JMenuItem. Menus can also contain separators, radio button menu items, and checkbox menu items.

A menu item can respond to clicks using an ActionListener.

This sandbox cannot display GUI windows — run this code locally in your IDE to see the frame. The example below prints what would render.