pRINTING AN OBJECT WITH NULL REFERENCE

[Porchelvi Vendhan]

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

[leena rane]

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

[Jane Griscti]

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

[marilyn murphy]

>When the following code is executed:

<font size=+0>
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?

The System.out.println( obj ) method changes the obj to a String by calling
String.valueOf( obj );
Since, as Leena explained, the objects are initialized to null, "If the argument is null then the string "null" is printed" (API)
[This message has been edited by marilyn murphy (edited September 22, 2001).]

[Marilyn de Queiroz]

Since there is another discussion of this same question in another thread, I am closing this one.