Java Collection Classes in vCO

From the documentation I see by default classes from java.util.* available for vCO Java Script Engine.

I am using vCO 5.1 appliance version.

Can any one post an example on how to use HashMap or ArrayList directly from vCO java script.

I tried this kind of pattern. But no use.

     var aList = new ArrayList();    

     aList.add('Hello');

Appreciate any help.