mock exam

[sun par]

public class MyClass
{
final int i ;
public static void main(String[] arguments)
{
System.out.println(new MyClass().i);
}
}
-----------------------------
Fails to compile saying that i is not initialized. Why is it so when i is an instance variable?
Thanks

[sun par]

class MyClass
{
public static void main (String args[])
{
String s1[] = new String[5];
String str = s1[0].toUpperCase();
System.out.println(str);
}
}
----------------------------------------------
this gives null pointer exception.Why is it so?
Thanks

[Shishio San]

Hi,
An instance final variable has to be initialized before being used inside a constructor or an instance initializer.
When constructing your String array, it was initiliazied to null and therefore you're trying to use null in a case where an object is required. That triggers the NullPointerException
Hope this helps

[sun par]

Thanks Shisho.. am able to understand now...

[Shishio San]

Good for you