Programming Tree

package layosa_treebinary;

import java.util.Collections;
import javax.swing.JFrame;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;

public class layosa_treebianry extends JFrame {
    JTree tree;
    
public layosa_treebianry() {
    DefaultMutableTreeNode html = new DefaultMutableTreeNode("html");
    DefaultMutableTreeNode head = new DefaultMutableTreeNode("head");
    DefaultMutableTreeNode body = new DefaultMutableTreeNode("body");
    html.add(head);
    html.add(body);
    
    DefaultMutableTreeNode meta = new DefaultMutableTreeNode("meta");
    DefaultMutableTreeNode title = new DefaultMutableTreeNode("title");
    head.add(meta);
    head.add(title);
    
    DefaultMutableTreeNode u1 = new DefaultMutableTreeNode("u1");
    DefaultMutableTreeNode h1 = new DefaultMutableTreeNode("h1");
    DefaultMutableTreeNode h2 = new DefaultMutableTreeNode("h2");
    body.add(u1);
    body.add(h1);
    body.add(h2);
    
    DefaultMutableTreeNode li1 = new DefaultMutableTreeNode("li");
    DefaultMutableTreeNode li2 = new DefaultMutableTreeNode("li");
    u1.add(li1);
    u1.add(li2);
    
    DefaultMutableTreeNode a = new DefaultMutableTreeNode("a");
    h2.add(a);
    
    System.out.println("4.1 Root Node: " + html.getRoot());
    System.out.println("4.2 Parent Nodes: " + head.getParent() + "' "
                                         + meta.getParent() + ", " 
                                         + u1.getParent() + ", " 
                                         + li1.getParent() + ", " 
                                         + a.getParent());
    System.out.println("4.3 Siblings: " + body.getPreviousSibling() + " and " + head.getNextSibling()
                                    + " , " + title.getPreviousSibling() + " and " + meta.getNextSibling()
                                    + " , " + li1.getNextSibling() + " and " + li2.getPreviousSibling());
    System.out.println("4.4 One-level subtrees: " + "\n" + " html - " + Collections.list(html.children())
                                                + "\n" + " head - " + Collections.list(head.children())
                                                + "\n" + " body - " + Collections.list(body.children())
                                                + "\n" + " u1 - " + Collections.list(u1.children())
                                                + "\n" + " h2 - " + Collections.list(h2.children()));
    System.out.println("4.5 Nodes per level: " + "\nLevel" + html.getLevel() + " - html"
                                            + "\nLevel" + head.getLevel() + " - head , body"
                                            + "\nLevel" + meta.getLevel() + " - meta, title, u1, h1, h2"
                                            + "\nLevel" + li1.getLevel() + " - li, li");
    System.out.println("4.6 Depth: " + html.getDepth());
    System.out.println("4.7 Degree of each one-level subtree: " + "html - " + html.getDepth()
                                                            + "\n" + "head - " + head.getDepth()
                                                            + "\n" + "body - " + body.getDepth()
                                                            + "\n" + "u1 - " + u1.getDepth()
                                                            + "\n" + "h2 - " + h2.getDepth());
    System.out.println("4.8 List of nodes based on: ");
    System.out.println("breadth - first: " + Collections.list(html.breadthFirstEnumeration()));
    System.out.println("breadth - first: " + Collections.list(html.preorderEnumeration()));                                        
    System.out.println("breadth - first: " + Collections.list(html.postorderEnumeration()));
                                            
    tree = new JTree(html);
    
    add(tree);
    this.setTitle("JTree Example");
    this.setSize(300,300);
    this.setVisible(true);
    
              
}
    public static void main(String[] args){
        new layosa_treebianry();
    }
}