Thanks for the reply, but I do not know if this is going to help me too much, I might be wrong, I am fairly new to JPA. Let me clarify a bit. My ResultSet from a Callable Statement returns an unknown number of fields, which I cannot specify at design time to map to fields of a POJO. The only alternative I can see, is if somehow the ResultSetMetaData for this ResultSet can be used by the ejb Query if have executed to map all fields to various keys of a Map with a List of values for the specific column or a single Object per key if there is only 1 row. Is this at all possible? Any help always appreciated. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982874#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...