multiselect form inputs only populate first string selected

When I try to use a multiselect input (html:select multiple="true"), it works fine as long as the associated property is a String[]. However, there's a situation where I have a dynamic list of form elements, each of which has its own multiselect input. So I tried changing the property to a List, bu

multiselect with a map-backed form property

I have a form with a dynamically generated list of constraints that can be turned on or off, and each constraint has a set of values associated with it. My form has two relevant fields: private String[] selectedConstraints; private Map values; public String[] getSelectedConstraints() { return