Issue With ArrayList

[jagadesh]

Hi Guys,

While i Was Working , I got to learn that
Defining an ArrayList with size is more better that defining it
without size

according to the performance Tips,

ArrayList my=new ArrayList(10);

works faster that ArrayList my=new ArrayList(10);

what is the difference and
Checking for null also takes much time when compared to the
performances.

is it true

Can u please Guide Me guys

 

[Roedy Green]

ArrayList my=new ArrayList(10);

works faster that ArrayList my=new ArrayList(10);

I think you meant:

ArrayList my = new ArrayList(10);
works faster than
ArrayList my = new ArrayList();

That is not true.

However:
ArrayList my = new ArrayList(100);
works faster than
ArrayList my = new ArrayList();
If you have 100 elements. However if you have only 10, then
ArrayList my = new ArrayList();
works faster.

new ArrayList() is just shorthand for new ArrayList(10).
They have exactly the same meaning.

Normally you specify the content type e.g.

ArrayList<String> my = new ArrayList<String>(100);
--
Roedy Green Canadian Mind Products
http://mindprod.com
Your old road is
Rapidly agin'.
Please get out of the new one
If you can't lend your hand
For the times they are a-changin'.

 

[jagadesh]

Thanks For The Answers Guys
Thanks Very much .
i Will Follow The Rules

 

[Arne Vajhøj]

While i Was Working , I got to learn that
Defining an ArrayList with size is more better that defining it
without size

according to the performance Tips,

ArrayList my=new ArrayList(10);

works faster that ArrayList my=new ArrayList(10);

what is the difference and
Checking for null also takes much time when compared to the
performances.

is it true

No.

But you should not waste your time on microscopic optimizations
like this.

Arne