Jtree

 import java.awt.Container;  
 import java.awt.FlowLayout;  
 import javax.swing.JFrame;  
 import javax.swing.JTree;  
 import javax.swing.tree.DefaultMutableTreeNode;  
 class Demo extends JFrame{  
   JTree jt;  
   Demo(){  
     DefaultMutableTreeNode a=new DefaultMutableTreeNode("A");  
     DefaultMutableTreeNode b=new DefaultMutableTreeNode("B");  
     DefaultMutableTreeNode c=new DefaultMutableTreeNode("C");  
     DefaultMutableTreeNode d=new DefaultMutableTreeNode("D");  
     Container c1=getContentPane();  
     c1.setLayout(new FlowLayout());  
     setSize(500,500);  
     a.add(c);  
     a.add(b);  
     b.add(d);  
     jt =new JTree(a);  
     c1.add(jt);  
     }  
 }  
 public class Tree {  
   public static void main(String arg[]){  
     Demo d=new Demo();  
     d.setVisible(true);  
   }  
 }