Re: which collection to use

From:

Thomas Hawtin <usenet@tackline.plus.com>

Newsgroups:

comp.lang.java.programmer

Date:

Sat, 23 Dec 2006 14:40:10 +0000

Message-ID:

<458d3fb9$0$8738$ed2619ec@ptn-nntp-reader02.plus.net>

gaurav v bagga wrote:

r
2405892
r
832229

Yeah, I get:

r
617475
r
187102

Oh, but I switched and did TreeMap first...

it seems tree is better or is it that I am measuring the speed in wrong
way?

Most modern JREs use adaptive compilers. They will start interpreting
code and gradually compile bits and pieces, perhaps the same piece a
number of times.

So you need to be extremely careful. Assuming you care about 'hot
spots', then your microbenchmarks should loop many times and alternate
between algorithms. Better, use real code.

One things microbenchmarks don't cover is seas of not very warm code.
Apparently Swing is like this. For good performance there you need to
write less code ("there is no code faster than no code").

Either way you tend to get better performance, surprisingly, by keeping
methods small (Swing is really bad at this). In particular keep
low-level hot spots away from less well used code (Swing is really bad
at this). And factor out common code as best you can (Swing is really
bad at this).

Tom Hawtin