array of structures, or structure of arrays?

Question

Hmmm. I have a table which is an array of structures I need to store in Java. The naive don\'t-worry-about-memory approach says do this:

public class Record          


        

Answer 1

Because you are making the int[] fields final, you are stuck with just the one initialization of the array and that is it. Thus, if you wanted 10^6 field1's, Java would need to separate that much memory for each of those int[], because you cannot reassign the size of those arrays. With an ArrayList, if you do not know the number of records beforehand and will be removing records potentially, you save a lot of space upfront and then later on as well when you go to remove records.