Multi value checkbox parameters into a report

[edensh]

Hi,

I have a JasperServer report with a multi-select query (checkbox) input control. It fills up and I perform the selection. I saw that the type of parameter should be java.util.ArrayList.

My query:

select X from Y
where
  X in $P{Param}

When executing I get that ArrayList isn't a valid parameter for the query.

What am I missing?