difference between ArrayList - Vector

[Sofie Deceuninck]

I want to make an array where the size is variable.
What's the difference when I use an ArrayList or a Vector?

[Ernest Friedman-Hill]

Hi Sofie,
Vector is older; ArrayList was introduced with JDK 1.2. The main difference is that Vector's methods are synchronized, while ArrayList's are not. Synchronized methods effect how the class will behave in a multi-threaded program. They make the class "safer," but at the expense of a little performance.
Most new code should use ArrayList. If you need a synchronized list, you can use Collections.synchronizedList(myArrayList). There's little reason to use Vector in new code (except when you need one to pass to an older method that wants a Vector as an argument.)
I'm going to move this to the Java in General (Intermediate) forum, where this discussion would be more at home.
[ February 20, 2004: Message edited by: Ernest Friedman-Hill ]