import java.awt.BorderLayout; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTree; import javax.swing.tree.DefaultMutableTreeNode; public class DefaultMutableTreeNodeAddingDemo { public static void main(String args[]) { JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root"); DefaultMutableTreeNode mercury = new DefaultMutableTreeNode("Mercury"); root.add(mercury); DefaultMutableTreeNode venus = new DefaultMutableTreeNode("Venus"); root.add(venus); DefaultMutableTreeNode mars = new DefaultMutableTreeNode("Mars"); root.add(mars); JTree tree = new JTree(root); JScrollPane scrollPane = new JScrollPane(tree); frame.add(scrollPane, BorderLayout.CENTER); frame.setSize(300, 150); frame.setVisible(true); } }