what is th use of converting an array list into an array ?

i don't know,but you can separte a list into another array.

generally , not much. but its good to have the option i suppose. Unless your doing something really big , or doing some testing , doesnt matter much.
you may like reading this .

what if you have to use that List as a parameter that 'll accept only arrays?

commented: polymorphism :) +4

NO. But arrays are dfferent List is different.
List interface is implements the Random interface