How many objects are created ?

[Serena Zhou]

Hi, I am a little puzzled about the anonymous inner class. How many objects are created in the following code?

  
class Food{
Popcorn p = new Popcorn(){  //line 2
public void pop(){          //line 3
// Some code here           //line 4
}                           //line 5
};                          //line 6
}

We know that instance variable p of type Popcorn references to an instance of the anonymous inner subclass class of Popcorn. Do you think that an instance of Popcorn has to be created for p? How many objects are created from line 2 to 6?
Thanks!
[ April 16, 2004: Message edited by: Serena Zhou ]

[Nathaniel Stoddard]

Only one object is created from lines 2-6. That's what the "new" operation does. As far as object allocation is concerned, in this case the fact that it is an anonymous class is not important. It is not different from "String p = new String;".
Now, if you had simply done an inner class (not anonymous with the new operator), or a static inner class, then the object allocation wouldn't happen until explicitly called by a client:

new Outer().new Inner();

[Serena Zhou]

I see. Thanks!

[Jeroen Wenting]

Of course more objects can be created if the constructor for PopCorn does so, but unless that constructor is specifically shown or mentioned you cannot know what it does so the exam will assume it does nothing that influences the answer of the question.