Why Vector

[Belisarius]

I've been poking around a few Java forums, and notice a lot of people use Vector. Why? It's slow and designed for threaded operations. Why don't more people use ArrayList? I use Vectors nowadays only when I want to synchronize data across threads.

[npa]

Originally posted by Belisarius
I've been poking around a few Java forums, and notice a lot of people use Vector. Why? It's slow and designed for threaded operations. Why don't more people use ArrayList? I use Vectors nowadays only when I want to synchronize data across threads.

Because somewhere, someone thought it was a good
idea...

It baffles me too (but my teacher in school told me to
use them).

[Belisarius]

Well, my professor basically thinks of Vector as a mistake. And if anyone should know, it's him, being that he basically wrote Collections.

It's good having actually language designers as professors.

[technobard]

I could be wrong on this, but I think Vector came out before ArrayList. A lot of older sample code probably uses Vector. When I started using Java, I took the 5-day class from Sun (which didn't include much, if any, info on Collections). The rest I picked up as I used it or needed it. I use a lot of Vector and Hashtable, even though I know that ArrayList and HashMap are the preferred alternatives. It's just habit and laziness. The execution speed thing only matters when you're doing something so speed intensive that you notice. If you're not writing that kind of code, which a lot of people aren't, you can't tell the difference.

[Belisarius]

Granted, there's no point in going back through all your old code to replace Vector with ArrayList when the old code works, but that doesn't explain why people continue to use it (and even worse, tell other people to use it).

It's just a flawed class (which, BTW, isn't even going to really exist in 1.5, it's just going to be a front-end to a new collection). It's synchronized but not thread safe. Ugh.

[technobard]

Originally posted by Belisarius
...but that doesn't explain why people continue to use it (and even worse, tell other people to use it).

Laziness, inertia, etc. Take your pick. Telling other people to use it is probably just not knowing any better. Personally, I try to tell people to use HashMap instead of Hashtable even though I've never done it. And I usually mention (if prompted), that there are better alternatives to Vector. But if I need to crank out a quick utility or something, the chances are good that I won't take my own advice. I've done it a hundred times before, I know the syntax, and I know it will work for what I'm doing.

I would hope that professional programmers / developers are better about this sort of thing. I think you mentioned that you were a student, so you probably fall into this category because of your intended profession. I'm an ex-engineer turned DBA (many, many moons ago) who happens to program occasionally. These days, mostly I write things to make my life easier. I've written enough code over the years in enough languages that I can usually figure out how to write anything I need. But no one would ever accuse me of following programming best practices. I suspect there are a lot of people out there like me. Maybe that explains some of what you're seeing.

Later.