XML : Unable To Save Java Object To XML File

I want to save my Object Mall into XML, however it doesn't seem to save when I open the XML file. Is it because there are too many objects within the Mall class to be saved therefore it can't be saved?

Below are my codes :

Mall Class

     public class Mall implements ActionExecute,Serializable {        private static Mall singleton = null;      private  ArrayList<Store> storeList = new ArrayList ();      private  ArrayList<Customer> customerList = new ArrayList ();      public static Mall instance()      {          if(singleton == null)          {              singleton = new Mall();            }         return singleton;      }      public void createStore(String factory,String storeType,String storeName)        {              AbstractFactory Factory  = FactoryProducer.getFactory(factory);              if(factory.equals("store"))            {            Store newstore = Factory.getStore(storeType,storeName);            storeList.add(newstore);            }               }    

SaveFile Class

  public class saveFile {   public static void write(Mall f) throws Exception{       try (XMLEncoder encoder = new XMLEncoder(                                    new BufferedOutputStream(                                      new FileOutputStream("designpattern.xml")))) {           encoder.writeObject(f);       }  }  }    

XML file Result

  <?xml version="1.0" encoding="UTF-8"?>  <java version="1.7.0_25" class="java.beans.XMLDecoder">  <object class="designpattern.Mall"/>  </java>