iterating over a list / set can be done via;
<c:forEach items=”${job.jobPhotos}” var=”photo” varStatus=”idx”>
<form:hidden path=”jobPhotos[${idx.index}].id” />
Iterating over a map can be done via;
<c:forEach items=”${job.jobPhotos}” var=”current”>
<form:hidden path=”jobPhotos[${current.key}].id” />
${current.key} and ${current.value.id} are equilivant (both equate to the ID of the row being iterated over)
http://www.steve-farmer.com/examples/jstl/ui/c-foreach-map.jsp