Java swing code for creating a simple tree

//package swing;
//import statements
import javax.swing.*;
import javax.swing.tree.*;
import java.util.*;
import java.awt.*;
/**
* SimpleTreeFrame.java
* This class shows how to create a simple JTree
* using DefaultMutableTreeNode
*/
public class SimpleTreeFrame extends JFrame {
	public static final String RPG = "Role Playing Games";
	public static final String FPS = "First Person Shooters";
	public static final String SP = "Sports";
	public static final String GAMES = "GAMES";
	//JTree tree
	private JTree m_simpleTree;
	//Tree root node
	private DefaultMutableTreeNode m_rootNode;
	public SimpleTreeFrame() {
		super("Simple Tree Demo");
		//creating tree nodes
		createTreeNodes();
		//creating JTree by passing the root node
		m_simpleTree = new JTree(m_rootNode);
		//Add the JTree to the scroll pane to handle tree scrolling
		JScrollPane scrollPane = new JScrollPane(m_simpleTree);
		//add the scroll pane to the frame
		getContentPane().add(scrollPane);
	}
	/**
	* createTreeNodes
	* This function creates tree nodes
	*/
	private void createTreeNodes() {
		//creating the root node
		m_rootNode = new DefaultMutableTreeNode(GAMES);
		//creating different domain nodes
		DefaultMutableTreeNode rpgNode = new DefaultMutableTreeNode(RPG);
		DefaultMutableTreeNode fpsNode = new DefaultMutableTreeNode(FPS);
		DefaultMutableTreeNode spNode = new DefaultMutableTreeNode(SP);
		//get the dummy data vector
		Vector data = getDummyData();
		//Enumerating the vector, create the machine nodes by passing MachineData
		//as UserObject and add the nodes under proper domain
		for (Enumeration enum = data.elements(); enum.hasMoreElements();) {
			GameData macData = (GameData) (enum.nextElement());
			if (macData.getGameDomain().equals(RPG)) {
				rpgNode.add(new DefaultMutableTreeNode(macData));
			} else if (macData.getGameDomain().equals(FPS)) {
				fpsNode.add(new DefaultMutableTreeNode(macData));
			} else if (macData.getGameDomain().equals(SP)) {
				spNode.add(new DefaultMutableTreeNode(macData));
			}
		}
		//adding domain nodes to the organization root node
		m_rootNode.add(rpgNode);
		m_rootNode.add(fpsNode);
		m_rootNode.add(spNode);
	}
	/**
	* getDummyData
	* This function creates Vector of dummy GameData objects and returns it
	*/
	private Vector getDummyData() {
		Vector dummyMacData = new Vector(10, 10);
		dummyMacData.addElement(
			new GameData(
				new Integer(100),
				"World of Warcraft",
				"PC",
				RPG));
		dummyMacData.addElement(
			new GameData(
				new Integer(105),
				"Guild Wars",
				"PC",
				RPG));
		dummyMacData.addElement(
			new GameData(
				new Integer(110),
				"Fable",
				"XBOX",
				RPG));
		dummyMacData.addElement(
			new GameData(
				new Integer(106),
				"EverQuest",
				"PC",
				RPG));
		dummyMacData.addElement(
			new GameData(
				new Integer(302),
				"Fifa",
				"ALL",
				SP));
		dummyMacData.addElement(
			new GameData(
				new Integer(303),
				"ISSoccer",
				"All",
				SP));
		dummyMacData.addElement(
			new GameData(
				new Integer(305),
				"Tennis",
				"All",
				SP));
		dummyMacData.addElement(
			new GameData(
				new Integer(504),
				"Halo",
				"XBOX",
				FPS));
		dummyMacData.addElement(
			new GameData(
				new Integer(505),
				"Quake",
				"PC",
				FPS));
		dummyMacData.addElement(
			new GameData(
				new Integer(104),
				"Halflife",
				"PC",
				FPS));
		return dummyMacData;
	}
	/**
	* GameData.java
	* The data object to store the Game Information
	*/
	public class GameData {
		private Integer m_gmCode;
		private String m_gmName;
		private String m_gmFormat;
		private String m_gmDomain;
		public GameData() {
		}
		public GameData(
			Integer gmCode,
			String gmName,
			String gmFormat,
			String gmDomain) {
			m_gmCode = gmCode;
			m_gmName = gmName;
			m_gmFormat = gmFormat;
			m_gmDomain = gmDomain;
		}
		public Integer getGameCode() {
			return m_gmCode;
		}
		public String getGameName() {
			return m_gmName;
		}
		public String getGameIP() {
			return m_gmFormat;
		}
		public String getGameDomain() {
			return m_gmDomain;
		}
		
		public void setGameCode(Integer gmCode) {
			m_gmCode = gmCode;
		}
		public void setGameName(String gmName) {
			m_gmName = gmName;
		}
		public void setGameIP(String gmFormat) {
			m_gmFormat = gmFormat;
		}	
		
		public void setGameDomain(String gmDomain) {
			m_gmDomain = gmDomain;
		}	
		public String toString() {
			return (
				new String(
					m_gmCode
						+ ": "
						+ m_gmName
						+ " ("
						+ m_gmFormat
						+ ") " ));
		}
	}
	/**
	* main
	*/
	public static void main(String[] arg) {
		SimpleTreeFrame m = new SimpleTreeFrame();
		m.setVisible(true);
		m.setSize(new Dimension(450, 300));
		m.validate();
	}
}