Java tutorial
import java.awt.BorderLayout; import java.awt.Color; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTree; import javax.swing.LookAndFeel; import javax.swing.UIDefaults; import javax.swing.UIManager; public class MainClass { public static void main(String args[]) { JFrame frame = new JFrame("Lazy Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Object iconObject = LookAndFeel.makeIcon(MainClass.class, "yourImage.gif"); UIManager.put("Tree.leafIcon", iconObject); Integer fifteen = new Integer(15); Object lazyArgs[] = new Object[] { Color.GREEN, Boolean.TRUE, fifteen, fifteen }; Object lazyDiamond = new UIDefaults.ProxyLazyValue("DiamondIcon", lazyArgs); UIManager.put("Tree.openIcon", lazyDiamond); JTree tree = new JTree(); JScrollPane scrollPane = new JScrollPane(tree); frame.add(scrollPane, BorderLayout.CENTER); frame.setSize(200, 200); frame.setVisible(true); } }