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doesnt look like a Microsoft question !!!

koi to answer do

koi to answer do

It took me a while to understand this. By default B[0] , [1] and [2] are null. When you initialize the array, corresponding objects constructor is not called. Hence mentioned line cause nullpoiterassignment exception.

In method gen(), before assigning value C1.B1[0].x=5, first assign an object to location B1[0]. working gen() method is as follows:

static void gen(c C1)
{
C1.B1[0]=new b();
C1.B1[1]=new b();
C1.B1[2]=new b();
C1.B1[0].x=5;//bug in the line
C1.B1[1].x=6;
C1.B1[2].x=7;
}

yep sur is right, when we declare an array of object, we have to redefine each element separately and also i think x should be declared static since we are directly using it with the class name, can anybody confirm that

The problem is in class C
class c
{
b B1[]=new b[3];
}

when class C is instantiated, 3 new reference variables are created (in stack), but they don't point to any object(in heap). So C1.B1[0].x will throw npe

class c
{
b B1[]={new b(), new b(),new b()};
}

I suppose, this will solve the problem.

nullpointexception