array of objects

[Time]

Hi ppl,
whenever we write

class object=new class();

object gets created; assigning values to it is perfectly fine.
now in case of array objects:

class object[]=new class[3];

i had assigned values to

object[0]...3

by

object[0].variable

..its syntactically right but giving run-time error of null pointer assignment.
Whenever we create an object of any class its a reference variable untill memory is assigned to it..
but we are clearly using new operator and allocating memory to each object in object array.....where am i mistaking?

[Curtis Rutland]

I could be wrong, but if Java is like some of the other OOP languages I worked with, when you do this:

class object[] = new class[3];

You are actually creating a new array, and allocating the memory space for three pointers, but you are not initializing any of those three new objects.

You still need to initialize each object in the array before you can use them:

object[0] = new class();

Or as a loop:

for(int i=0; i<3; i++)
  object[i] = new class();

I hope that is correct and helps.

[Time]

Yeah i agree with you; that they are not initialized; but

object[0]=new class();

allocates memory as new is used and not just initialization..

[Curtis Rutland]

I'm afraid I don't understand your question here.

but we are clearly using new operator and allocating memory to each object in object array

That's not quite true. You're just allocation the memory for a pointer. Those pointers are null. You have to initialize each object in the array if you want to use them.

If that's not what you are asking, please clarify your question.

[pbrockway2]

@Time
The line of quote you quoted comes from insertAlias and that does create a new (class) object.

Your code was "class object[]=new class[3];" and what that does is create a new array.

Think of the array as a box - with little slots in it marked zero to two. Creating a box (an empty one) is one thing. Creating objects to put in the box is quite another.