Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.programmer > #10117

Re: Size of an arraylist in bytes

Show all headers | View raw

On Nov 20, 1:30 pm, Eric Sosman <esos...@ieee-dot-org.invalid> wrote:
> On 11/20/2011 4:01 PM, sara wrote:
>
> > Hi All,
>
> > I create an Arraylist<Integer>  tmp and add some integers to it.
> > Afterward, I measure the size of tmp in bytes (by converting tmp to
> > bytes array). Assume the result is byte[] C. However, when I update an
> > element of tmp, and measure size of tmp in bytes again, the result is
> > different than C!
> > Why this is the case?
>
>      See markspace's response.  Another possible point of confusion:
> The ArrayList does not actually contain objects, but references to
> those objects -- that's why the same object instance can be in three
> ArrayLists, two Sets, and a Map simultaneously.  In fact, the same
> Integer object could appear forty-two times in a single ArrayList:
>
>         List<Integer> list = new ArrayList<Integer>();
>         Integer number = Integer.valueOf(42);
>         for (int i = 0; i < 42; ++i)
>             list.add(number);
>
>      If you're coming from a C background, a rough analogy is that
> the ArrayList holds "pointers" to the objects it holds, not copies
> of those objects.
>
> --
> Eric Sosman
> esos...@ieee-dot-org.invalid

But do you have any answer to my second question?

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Size of an arraylist in bytes sara <sarasara82@gmail.com> - 2011-11-20 13:01 -0800
  Re: Size of an arraylist in bytes markspace <-@.> - 2011-11-20 13:05 -0800
    Re: Size of an arraylist in bytes sara <sarasara82@gmail.com> - 2011-11-20 13:11 -0800
      Re: Size of an arraylist in bytes Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-20 21:58 +0000
      Re: Size of an arraylist in bytes markspace <-@.> - 2011-11-20 14:08 -0800
      Re: Size of an arraylist in bytes Patricia Shanahan <pats@acm.org> - 2011-11-20 14:50 -0800
      Re: Size of an arraylist in bytes Arne Vajhøj <arne@vajhoej.dk> - 2011-11-20 18:06 -0500
      Re: Size of an arraylist in bytes Lew <lewbloch@gmail.com> - 2011-11-20 20:28 -0800
  Re: Size of an arraylist in bytes Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-20 16:30 -0500
    Re: Size of an arraylist in bytes sara <sarasara82@gmail.com> - 2011-11-20 13:35 -0800
      Re: Size of an arraylist in bytes Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-20 17:19 -0500
    Re: Size of an arraylist in bytes Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-20 16:58 -0500
      Re: Size of an arraylist in bytes Patricia Shanahan <pats@acm.org> - 2011-11-20 14:04 -0800
        Re: Size of an arraylist in bytes Arne Vajhøj <arne@vajhoej.dk> - 2011-11-20 17:18 -0500
          Re: Size of an arraylist in bytes Patricia Shanahan <pats@acm.org> - 2011-11-20 14:48 -0800
            Re: Size of an arraylist in bytes Arne Vajhøj <arne@vajhoej.dk> - 2011-11-25 22:12 -0500
      Re: Size of an arraylist in bytes Lew <lewbloch@gmail.com> - 2011-11-20 20:44 -0800
        Re: Size of an arraylist in bytes Arne Vajhøj <arne@vajhoej.dk> - 2011-11-25 22:16 -0500
          Re: Size of an arraylist in bytes Lew <lewbloch@gmail.com> - 2011-11-25 20:15 -0800
  Re: Size of an arraylist in bytes Roedy Green <see_website@mindprod.com.invalid> - 2011-11-20 22:25 -0800
    Re: Size of an arraylist in bytes Arne Vajhøj <arne@vajhoej.dk> - 2011-11-25 22:11 -0500

csiph-web