• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Jeanne Boyarsky
  • Ron McLeod
  • Paul Clapham
  • Liutauras Vilda
Sheriffs:
  • paul wheaton
  • Rob Spoor
  • Devaka Cooray
Saloon Keepers:
  • Stephan van Hulst
  • Tim Holloway
  • Carey Brown
  • Frits Walraven
  • Tim Moores
Bartenders:
  • Mikalai Zaikin

pRINTING AN OBJECT WITH NULL REFERENCE

 
Greenhorn
Posts: 21
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi!
When the following code is executed:
public class Test{
static String s1;
static Integer i1;

public static void main (String args [])
{
System.out.println(s1);
System.out.println(i1);
}
}
null
null
gets printed instead of throwing a NullPointerException.
Can someone please explain why?
Thanks
Porchelvi
 
Ranch Hand
Posts: 280
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

public class Test{
static String s1;
static Integer i1;
public static void main (String args [])
{
System.out.println(s1);
System.out.println(i1);
}
}

Since s1 and i1 are member variables they are automatically initialised to default value(null)
It is as good as writing
static String s1=null;
static Integer i1=null;
But if u have something like this:
public class Test{
public static void main (String args [])
{
static String s1;
static Integer i1;
System.out.println(s1);
System.out.println(i1);
}
}
It will not compile,because now they are in a method body they will not be initialized to default value(null)
Hope it helps
 
Ranch Hand
Posts: 3141
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Porchelvi,
I'm going to move this over to Certification Study as the question is not related to a mock exam error.
------------------
Jane Griscti
Sun Certified Programmer for the Java� 2 Platform
 
So I left, I came home, and I ate some pie. And then I read this tiny ad:
a bit of art, as a gift, that will fit in a stocking
https://gardener-gift.com
reply
    Bookmark Topic Watch Topic
  • New Topic