Instances and members

Question

In the program below, the first println() produces "true".
The second println() yields a compile time error - "cannot find symbol 'x' "
If "obj" is indeed a "Foobar", why does the compiler not see its 'x' member?
Thank you.
public class NewInstance
     public static void main(String[] params) throws Exception
          Foobar foobar = new Foobar();
          Object obj = foobar.getClass().newInstance();
          System.out.println(obj instanceof Foobar);
          System.out.println(obj.x);
class Foobar
     int x = 123;
}

Answer 1

I'm trying to see if I can write a program that
instantiates a class whose type is not known at
compile time.
Any hints?
I've tried all manner of permutations of reflection.String className = ...; // get the actual class name to instantiate here
Class clazz = Class.forName(className); // create the class
Object instance = clazz.newInstance(); // create an instance
Now what do you want to do with the instance? If you want to call methods on it, how are you going to do that unless you already know of some interface that the class implements? You wouldn't just create any willy-nilly class instance - you'd expect the one you're creating to implement a known instance.
MyInterface myInstance = (MyInterface) instance;
Now you can call whatever methods MyInterface defined.