array list and string[]

[pippiri venu]

which one is the best?
and why?

array list or string[]

[Ulf Dittmer]

That depends greatly on what you're doing with it. Arrays offer slightly better performance (there is less overhead to deal with), but ArrayList is more flexible (you can add and delete elements).
I prefer Collections for their convenience, which to me is almost always more important than speed.

[Layne Lund]

Before Java 5.0, arrays also provided type-checking that was missing from Collections (such as ArrayList). With generics, this is mitigated somewhat.

Layne