Inner Classes Mock question doubt 3

[Hardik Raja]

Hello Friends,

This is a question from K & B Book, Chapter Inner classes, Page 669

8. Given:
public class Foo {
Foo() {System.out.print("foo");}
class Bar{
Bar() {System.out.print("bar");}
public void go() {System.out.print("hi");}
}
public static void main(String[] args) {
668 Chapter 8: Inner Classes
Foo f = new Foo();
f.makeBar();
}
void makeBar() {
(new Bar() {}).go();
}
}
What is the result?
A. Compilation fails.
B. An error occurs at runtime.
C. foobarhi
D. barhi
E. hi
F. foohi
 
Answer:
C is correct because first the Foo instance is created, which means the Foo constructor
runs and prints foo. Next, the makeBar() method is invoked, which creates a Bar,
which means the Bar constructor runs and prints bar, and finally an instance is created
(of an anonymous subtype of Bar), from which the go() method is invoked. Note that the
line (new Bar() {}).go(); creates a little tiny anonymous inner class, a subtype of Bar.
 
A, C, D, E, and F are incorrect based on the program logic described above.

See the explanation of Option c..

I know the correct option is C...But I feel there is something wrong in its explantion..

It tells it creates bar and then finally creates instance of anonymous subclass of bar..??

I think only one instance is created and that is instance of anonymous subclass of bar

am i correct..??

BOTTOM LINE :
when makeBar() method is invoked, it creates an instance of anonymous subclass of bar, thus prints "bar"
and then it invokes method go() on the newly created instance, so "hi" is printed.

Regards,
Hardik.S.Raja
[ May 04, 2007: Message edited by: Hardik Raja ]

[Chandra Bhatt]

override the method go, inside the anonymous class and see the result:

void makeBar() {
(new Bar() {public void go() {System.out.println("Its my life");}}).go();
}

Output:
...
...
Its my life


Thanks,
cmbhatt

[Hardik Raja]

Ok I got my answer...

It means only one instance is created that of anonymous subclass of Bar..

Thanks...