Elements overwrites each others in Linked List

Question

hello, my problem is mentioned as the subject.
i'm trying to add the same object into a linked list each time with different values, however it doesn't work and eventually all objects stored in the linked list become identical.
here's the sample code.
public class Object1
     private String s = null;     
     public Object1(){}
     public void setS(String s){this.s = s;}
     public String getS(){return s;}
import java.io.*;
import java.util.List;
import java.util.LinkedList;
import java.util.Collections;
public class Test
     public static void main(String[] args)
          List ll = Collections.synchronizedList(new LinkedList());
          Object1 obj1 = new Object1();
          obj1.setS("111111");          
          ll.add(obj1);
          for (int i=0; i<ll.size(); i++)
               Object1 obj2 = (Object1)ll.get(i);
               System.out.println(">>>>>before:: " + obj2.getS() + "\n");
          obj1.setS("2222222");
          ll.add(obj1);
          for (int i=0; i<ll.size(); i++)
               Object1 obj2 = (Object1)ll.get(i);
               System.out.println(">>>>>after:: " + obj2.getS());          
and the result looks like this:
before:: 111111
after:: 2222222
after:: 2222222what i really want is something like this instead:
before:: 111111
after:: 111111
after:: 2222222could any one please help
thanks in advance
cedricc

Answer 1

You need to understand the distinction between references and objects. You're not storing objects in the linked list, but references. All of these references point to the same object. You need to create a new object each time through the loop.