Should we ever select ArrayList over HaspMap? If I am dealing with 3/5 key velue record, is it a better solution to use a user defined class which store Key, Value record and store them into ArrayList instead of directly using HashMap.

which one will occupy more memory and which class takes more time to create.

And what will be the case if records are more between 30/40.

Is there any place where I can find detailed comparision.