User-defined objects in collections

[Sharda Vajjhala]

I have a program as follows:

import java.util.*;
 
class Address{
    private String name;
    private String street;
    private String city;
    private String state;
    private String zipcode;
    
    Address(String n, String s, String c, String st, String z){
       name = n;
       street = s;
       city = c;
       state = st;
       zipcode = z;
    }
}
 
class MailList{
    public static void main(String args[]){
       LinkedList ml = new LinkedList();
       
       //Store user-defined objects 
       ml.add(new Address("John Doe","123 Street","Sacramento","CA","95758"));
       ml.add(new Address("Jane Doe","234 Street","Anywhere","NJ","95670"));
       ml.add(new Address("Tarzan","Robin Ct","Toronto","MI","12345"));
       ml.add(new Address("Jane Doe","234 Street","Anywhere","NJ","95670"));
       
       System.out.println("Mailing list is:");
       Iterator itr = ml.iterator();
       while(itr.hasNext()){
          Object element = itr.next();
          System.out.println(element +"\n");
       }   
    }
}

This prints out as follows:
Mailing list is:
Address@f56cf041
Address@f574f041
Address@f624f041
Address@f634f041
Why does it not print out the address contained within the element? It prints out the actual elements, if I use simple objects such as Strings
such as the following example:

/* Iterator eg  */
 
import java.util.*;
 
class IteratorEg{
   public static void main(String args[]){
      LinkedList al = new LinkedList();
      
      al.add("C");
      al.add("U");
      al.add("C");
      al.add("K");
      al.add("O");
      al.add("O");
      
      Iterator itr = al.iterator();
      while(itr.hasNext()){
         Object element = itr.next();
         System.out.print(element + " ");
      }
      System.out.println();
  }
}

Output of this is as follows:
C U C K O O
I would have expected the 1st MailingList program to print out the actual addresses(although not formatted properly).
Can anyone please explain?
Thanks
Sharda[ edited to preserve formatting using the [code] and [/code] UBB tags -ds ]
[ July 30, 2002: Message edited by: Dirk Schreckmann ]

[Snigdha Solanki]

That's because your address class does not override toString() method of Object Class.The toString method for Object class returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object.
For example - Address@f56cf041

[Stu Glassman]

When you output a class, the program actually calls MyClass.toString(). The Object class defines toString as returning ClassName@hashcode. In order to output the Address correctly add the following method:

public String toString() {
   return name + "\n" +
      street + "\n" +
      city + ", " + state + " " + zipcode;
}

Feel free to change the code to produce whatever formatting you'd like.
-Stu