I need to merge several arrays today in CF but I wanted to treat the resulting merged array as a set, where it only had items that are not duplicated. Java to the rescue, our good old Set interface and using a Tree set class.

All we need to do is use its awesome methods:

a1 = [1,2,3,4,5,6];

a2 = [2,6,8,4,99,0];

set = createObject("java","java.util.TreeSet").init(a1);

set.addAll(a2);

That's it. This merges the array collections and creates a sorted set without any duplicates. Quick and easy!