nullpointer exception while try to retrieve the elements from the array object

hi,
i had created the array object by using getter/setter method.while i
try to retrieve the elements from the array object. null pointer
exception raise in line no : 35 and line no: 64 .Any body help me to
over come my problem.here's my coding

//Sample .java for Menu to get List Object to a Array
//getter/setter method is in Menu.java

package example;

import org.jdom.*;
import org.jdom.input.SAXBuilder;
import org.jdom.Document;
import org.jdom.Element;
import java.util.*;
import java.io.*;

public class ParseXml
{

    public static void main(String[] args)
    {
        Menu mainMenu = new Menu();
        try{
            SAXBuilder builder = new SAXBuilder();
            Document doc = builder.build( new File("C:/Application/
Specification/ApplicationMenu.xml"));
            Element root = ( Element)doc.getRootElement();
            List listroot = root.getChildren();
            Iterator itr = listroot.iterator();
            while( itr.hasNext()){
                Element nextChild = ( Element)itr.next();

mainMenu.setDescription( nextChild.getAttribute( "description").getValue());
                mainMenu.setMenuID( nextChild.getAttribute( "id").getValue());
                getConsolidateMenu( mainMenu, nextChild, 0);
            }
        }catch( Exception e){
            e.printStackTrace();
        }
        printMenu( mainMenu);
    }
    public static void getConsolidateMenu( Menu menu, Element current,
int depth){
        printSpaces( depth);

System.out.println( current.getAttribute( "description").getValue());
        List list = current.getChildren();
        Iterator it = list.iterator();
        Menu mainMenu = new Menu();
        Menu [] subMenu = new Menu[list.size()];
        int i = 0;
        while( it.hasNext()){
            Element child = (Element)it.next();

mainMenu.setDescription( child.getAttribute( "description").getValue());
            mainMenu.setMenuID( child.getAttribute( "id").getValue());
            subMenu[i] = new Menu();

subMenu[i].setDescription(child.getAttribute( "description").getValue());
            subMenu[i].setMenuID( child.getAttribute( "id").getValue());
            mainMenu.setSubMenu( subMenu);
            getConsolidateMenu( mainMenu, child, depth + 1);
            i++;
        }
    }
    public static void printSpaces( int n){
        for( int i = 0; i <= n; i++){
            System.out.print( " ");
        }
    }
    public static void printMenu( Menu menu){
        Menu mainMenu = new Menu();
        Menu [] subMenu = mainMenu.getSubMenu();
        for( int i = 0; i < subMenu.length; i++){
            System.out.println( subMenu[i]);
        }
    }
}
//Menu Class for ParseXml.java getter/setter method

package example;

public class Menu
{
    String menuID;
    String description;
    Boolean isService;
    String serviceID;
    Menu [] subMenu;
    public void setMenuID( String menuID){
        this.menuID = menuID;
    }
    public String getMenuID(){
        return menuID;
    }
    public void setDescription( String description){
        this.description = description;
    }
    public String getDescription(){
        return description;
    }
    public void setIsService( Boolean isService){
        this.isService = isService;
    }
    public Boolean getIsService(){
        return isService;
    }
    public void setServiceID( String serviceID){
        this.serviceID = serviceID;
    }
    public String getServiceID(){
        return serviceID;
    }
    public void setSubMenu( Menu [] subMenu){
        this.subMenu = subMenu;
    }
    public Menu[] getSubMenu(){
        return subMenu;
    }
}
Thanks in advance,

cheers,
raja