Odd, I've never heard of Vector being suggested as faster than ArrayList. Given that ArrayList isn't syncronised it should be the faster one, where did you come across this particular snippit of 'wisdom'?
Well this is a quite general misunderstatement - since as far as I know ArrayList has different resizing charakteristis (more memory friedly).
My understanding of the history of Vector:
Vector was in the 1.0 libraries
By the time of 1.2 ArrayList had come along and people were switching to it for better performance. Vector was synchronised and because of that slower than the unsynchronised ArrayList.
By the time of 1.4 however the synchronisation mechanism was much much better - and Vector actually had a slight performance advantage over ArrayList.
If you're just repeating the old 1.2 mantra I recommend doing some performance testing with large Vectors and ArrayLists - and if you get roughly the same performance then you should switch to Vector because of its thread safety. (Advice I should take myself)
and of course many more unprofesisonal statements spread all over the web. However too tired fir searching them ;-)