I'm working away developing an app in Railo, and I just read Ben Nadel's post about how Coldfusion passes Arrays by Value (which is nuts btw, when you think about it) ... and how to pass an array By Reference using java.util.ArrayList directly.
Thankfully, Railo passes Arrays by Reference! ... and since I'm working on a new project there's no reverse compatibility issue moving from Coldfusion.
arrA = ArrayNew();
arrB = arrA;