aspose file tools*
The moose likes Programmer Certification (SCJP/OCPJP) and the fly likes Question on Integer type Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Certification » Programmer Certification (SCJP/OCPJP)
Bookmark "Question on Integer type" Watch "Question on Integer type" New topic
Author

Question on Integer type

Sneha Kapoor
Ranch Hand

Joined: Jun 08, 2009
Posts: 49
Hi All,



I thought answer would be 4 but answer is D

Can anyone please explain

Source : Whizlabs simulator

Thanks
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Rule : Instance class variables, if not initializes, assign null object and instance primitive variable, if not initialize, get assigned default (0) value.


[LEARNING bLOG] | [Freelance Web Designer] | [and "Rohan" is part of my surname]
Vijitha Kumara
Bartender

Joined: Mar 24, 2008
Posts: 3829



What this i refers to at runtime? That would give you the answer.


SCJP 5 | SCWCD 5
[How to ask questions] [Twitter]
Sneha Kapoor
Ranch Hand

Joined: Jun 08, 2009
Posts: 49
Thanks got it

I was null hence got null pointer
ram prabu
Greenhorn

Joined: Dec 23, 2008
Posts: 15
hi

The primitive instance variable default value is 0 (if not explicitly declared).
int i;
now i value is 0

Wrapper instance variable default value is null. Because the wrapper is object

Integer i;

now i value is null

Now the answer is null pointer exception because you are adding (null+value). No way to add by this way.

Thanks
Ram
Till Stoschus
Greenhorn

Joined: May 28, 2009
Posts: 14
Hi "ram prabu"

but the exception is thrown because the implicit Method call i.intValue() in "x = i+y;" refers on a null-value, right?

Till
ram prabu
Greenhorn

Joined: Dec 23, 2008
Posts: 15
hi
yes till
we got null pointer exception when we are adding null with value.

Thanks
Ram
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: Question on Integer type