Search:

The best way is to use collection, a List for example.

So do you want some kind of memory in your object to remember the results of all your accesses and computations?

yes. [code=Java] before, [//code] (with 1 slash) after

NullPointerException means, that you're trying to do something with null. Hence, check up every object in main() to be not null. Please, wrap your code in the [code=Java]/*...*/[//code] - it's really...

Update the array during each access...

Can you post the code here?