Action.SMALL_ICON has the following syntax.
static final String SMALL_ICON
In the following code shows how to use Action.SMALL_ICON field.
/* w ww . j av a 2 s . c o m*/ import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.KeyEvent; import javax.swing.AbstractAction; import javax.swing.Action; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.plaf.metal.MetalIconFactory; public class Main { public static void main(String[] a) { JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Action action = new ShowAction(); JButton button = new JButton(action); frame.add(button, BorderLayout.CENTER); frame.setSize(350, 150); frame.setVisible(true); } } class ShowAction extends AbstractAction { public ShowAction() { super("About"); putValue(Action.MNEMONIC_KEY, new Integer(KeyEvent.VK_A)); putValue(Action.SMALL_ICON, MetalIconFactory.getFileChooserHomeFolderIcon()); } public void actionPerformed(ActionEvent actionEvent) { System.out.println("About Swing"); } }