Observable and Observer

Question

I am trying to use Java Observable and Observer to notify the change in one object to other.
So i have to extend Observable class on the object which i want to montior on and
my observer class implements the observer to listen toupdate.
I have achieved the basic Observable and observer running.
Where I am having problem is, I couldn't figure out how to monitor, lets say 100 instance of the same object, with one object? I am not even
sure whether it is possible or not, if yes, can somebody tell me how
this can be achieved.
what i want to do in code
//The Observable class
public class Foo extends Observable {
    public void setFoo(String abc){
         //blah blah
         setChanged();
          notifyObservers();
//Observer class
public class observeFoo implements Observer{
    public void update(Observable o, Object oo){
        //blah blah
}Lets say i have 100 threads running each holding one instance of Foo
class. Is it possible to observe all those Foo instance running on each
thread by one observeFoo class? If yes how?
any help will be appreciated.
thanx in advance.

Answer 1

Just add the single Observer as an observer to all the observable objects. NotifyObservers() will do the rest.