How to typecast Object Class object dynamically

Question

Hai every one
i have a object of any particular class , but i don't know the variables in that class object. But i have string variable contains value of variables in that class object.
So i use following method for get value of variables in that class object.
class ObjectCLass
     Sub s=new Sub();
     public static void main(String[] args)
          ObjectCLass a=new ObjectCLass();
          try
               System.out.println(*a.getClass().getDeclaredField("s").get(a)*);
          catch(Exception e)
               System.out.println("Exception");
class Sub
     int i=5;
     public void print()
          System.out.println("Hello World!");
}Here the bolder line give Object class object. By using this Object class object i need access the variable i and method print(). So i need to cast Object class object into sub class
so how can i typecast it
i try with following methods , but i cant succeed
1.(  *(a.getClass().getDeclaredField("s").get(a).getClass)*   a.getClass().getDeclaredField("s").get(a)   ).print() ;
2.(  (Class.forName(�Sub�) ) a.getClass().getDeclaredField("s").get(a) ).print();Please any one one help me how to typecast it dynamically
By
Thiagu

Answer 1

If you know you're going to invoke the "print" method on an object, then you also need to know the type of the class, or interface, which has that method.
It seems what you are looking for is a tutorial on interfaces.
http://java.sun.com/docs/books/tutorial/java/IandI/index.html
In a nutshell, you can set up an interface which defines a "print" method, and create class(es) which implement that interface. Then as long as you have an object which implements that interface, but do not know the exact type of that object, you can simply cast it to the interface type and invoke the method.