Today I received a bug report. When I took a closer look at the bug, I realized that I used x.contains() method where x is a CF array. The code needs to determine if an integer is in the array x, and the java contains() method does exactly what I need. (FYI: CF array == java.utils.Vector)
However, since the array is from JSON, hell breaks loose...
<cfset a = [0,1,2]>
<cfset json = serializeJSON(a)>
<cfset b = deserializeJSON(json)>
You would think both cfdump will give you "YES", but they do NOT!
Why? if you try it you'll find that after serialized and deserialized to and from JSON, the array actually became [0.0,1.0,2.0] ! You may verify with #d.toString()# if you don't believe me.
So... how do I continue to use contains()? You would think
...and this finally returns 'YES'.
However, since my code need to work with both  and [0.0], I ended up writing the contains function in CFML instead with <cfloop> and <cfif>.
I thought I would save time by calling underlying java method, but I actually ended up spending more time fixing this 'bug'... For those who use underlying java methods in CF, watch out! Especially when you use JSON!