Thank you Robert. I too was confused...but as you said i think the
interviewer may not proficinet in Java :)

And it seems to mean something /really/ weird to the PHPers.  Not that the idea
of a default handler for undefined method calls is weird in itself, but calling
that technique "object overloading" makes no sense at all to me.

   -- chris

Thank chris...The interviewer insisted he did not mean other
overloading but object overloading. But i think the interviewer wanted
to paly a fool play..

The only interpretation of "object overloading" I can think of is  
something like Lisp's "let", which sets up a calling environment where the  
world looks different. However, this would be impossible in Java because  
each method call is isolated (except through parameters passed and the  
return value if any) so if a method used (pseudo-Java)

this.foo = new Foo();
let {
    this.foo = null;
}
for {
    this.doSomethingWithFoo(); // 1
}
this.doSomethingWithFoo(); // 2

the method doSomethingWithFoo(); would see the same value in both calls.  
Ideally call 1's manipulation of the null foo would be "forgotten" when  
the block exited, but this is complicated by multithreading (i.e. if you  
synthesized setting and resetting before and after the block, another  
thread would "see" the wrong (null) value if it executed the same time as  
the block).

You could emulate it by using a "context" object instead of instance  
variables, and passing that context around, but then you are really trying  
to reimplement Lisp in Java. :)