Class object in toString() form

Question

Hi there folks!
Simple question...
How can I obtain sttring representation of this vending machine using the standard toString convention of Java?
Thanks a lot for any help! : )
import java.lang.*;
import java.util.*;
import type.lang.*;
public class VendingMachine
    //VendingMachine constructor.
     public VendingMachine()
  // Adds items into VendingMachine collection.
     public void addItemType(ItemType item)
     ItemType aitem = item;
     String price  = aitem.getPrice()+"";
     int index = price.length();
     char check = price.charAt(index-1);
     if (list.size() == MAX_PERM)
     throw new RuntimeException("Maximum permitted amount reached");
    else  if ( check == '5' || check == '0')
     list.add(aitem);
    else
     throw new IncompatibleItemException("Price not allowed!");
    } //END of addItemType()
    //Accepts only coins of denomination 200, 100, 10 & 5.
    public void depositCoin(int cents)
    int acents = cents;
    String scents = ""+acents;
    StringTokenizer st = new StringTokenizer(DENOMINATION, ",");
    for(;st.hasMoreTokens();)
     listin.add(st.nextToken());
     if(listin.contains(scents))
     { depositamount += acents;} else
          throw new IllegalArgumentException("Not valid coin");
    }   //END depositCoin()
     public int getDepositAmount()
    return depositamount;
   } //END getDepositAmount()
     public int getBankAmount()
   int finalbank = bankamount + collected ;
    return finalbank;
   }//END of getBankAmount()
   public int clearMoney()
     if(bankamount < BANKAMOUNT)
          collected = 0;
     }else{
    collected = bankamount - BANKAMOUNT;
    return collected;
   }//END of clearMoney()
   //re-stocks a particular item
     public void reStock(int which, int qty)
  ((ItemType)list.get(which)).addItems(qty);
  } //END restock()
      //dispenses selected item, checks for sufficient amount deposited
      //checks for valid choice, checks for current stock available.
    public int selectItem(int which)
    selecteditem = which;   
    if(((ItemType)list.get(selecteditem)).getQuantity() < ONE)
    throw new OutOfStockException("Item out of Stock!");
    else if (depositamount < ((ItemType)list.get(selecteditem)).getPrice())
    throw new InsufficientPaymentException("Not enough payment!");
    else
    ((ItemType)list.get(selecteditem)).getItem();
   int change = depositamount - ((ItemType)list.get(selecteditem)).getPrice();
    return change;
  } //END selectItem()
    public void removeItemType(int which)
   list.remove(which);
  } //END removeItemType()
  //return items in formatted string
  public String showItems()
   StringBuffer buf = new StringBuffer();
   buf.append("Vending Machine Selection"+"\n");
   buf.append("========================="+"\n");
   if (list.size() > 0)
   for (int i = 0; i < list.size(); i++)
    buf.append(i + " for " + ((ItemType) list.get(i)).getName() + "\n ");  
  } else
    buf.append("Machine not Stocked."+"\n");
    return  buf.toString();
  public String toString()
       //***How can I represent object of this class as toString()?***
   private static final int ONE = 1;
   public static final int BANKAMOUNT = 2000;
   private final int MAX_PERM = 200; // maximum capacity of vending machine.
   private static final String DENOMINATION = "200,100,25,10,5";
   public int depositamount;//amount added into vending machine
   public int selecteditem;//item selected for dispensing
   public int collected;
   public int bankamount;
   private ArrayList list = new ArrayList(); //Collection of ItemType object reference
   private ArrayList listin = new ArrayList();//Collection of coin denomination permitted

Answer 1

You can make toString() return any String you want. Whatever makes sense.
Usually, I do this.
public String toString() {
   StringBuffer sb = new StringBuffer("VendingMachine");
   sb.append("[attr1=").append(attr1);
   sb.append("attr2,=").append(attr2);
   return sb.append("]").toString();
}Cuz that is typical of the AWT/Swing classes, but it doesn't matter, except that it usually in some way identifies the state of the object.