Hi, I posted this a week ago and didn't get a resolution - now I'm back on the case I would appreciate a few ideas on what else I could try:- Here's a bit more info (bean names etc sanitised to protect the innocent...) The main FormBean:- public class MyFormBean extends MyAncestorFormBean { private MyBean myBean = null; } The embedded bean:- public class MyBean extends SomeOtherBean { private Collection myCollection = null; private Collection myCollectionListData = null; } Relevant content of the JSP with the multi-select box:- Error log:- DEBUG 2004-03-01 15:15:39,437 [worker2] intuser@SessionID0 - org.apache.commons.beanutils.BeanUtils Target name = myCollection DEBUG 2004-03-01 15:15:39,447 [worker2] intuser@SessionID0 - org.apache.commons.beanutils.ConvertUtils Convert string 'Lalalalala' to class 'java.util.Collection' DEBUG 2004-03-01 15:15:39,447 [worker2] intuser@SessionID0 - org.apache.commons.beanutils.ConvertUtils Using converter org.apache.commons.beanutils.converters.StringConverter@3b1bc4 javax.servlet.ServletException: BeanUtils.populate at org.apache.struts.util.RequestUtils.populate(RequestUtils.java:1098) at org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.j ava:816) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:254) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1420) at bss.athena.framework.controller.FrameworkServlet.process(FrameworkServlet.ja va:149) at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:520) at javax.servlet.http.HttpServlet.service(HttpServlet.java:772) at javax.servlet.http.HttpServlet.service(HttpServlet.java:865) at com.persistence.web.JMillConnection.run(JMillConnection.java:1172) at com.persistence.web.JMillConnection.run(JMillConnection.java:292) at com.persistence.web.JMillThreadPool$WorkerThread.run(JMillThreadPool.java:96 ) Basically, I have a field on a page which is a multi-select box showing 7 items. The currently selected values are in "myCollection", the available values are in "myCollectionListData". The HTML