Help with Jsp: logic:iterate Cannot create iterator for this collection

Question

Hello,
I am developing a jsp with struts. This is the snap of the code:
        <logic:iterate id="prod" collection="productList" >
          <tr align="center">
               <td><html:text property="prodDesc" size="50" indexed="true"/></td>
               <td>
                    <html:select property="prodUnit" indexed="true">
                         <option selected>-</option>
                        <OPTION VALUE='NMB'>NMB
                         <OPTION VALUE='TEN'>TEN
                         <OPTION VALUE='TPR'>TPR
                         <OPTION VALUE='GWH'>GWH
                    </html:select>
               </td>
               <td><html:text property="prodQty" size="20" indexed="true"/></td>
               <td><html:text property="prodVal" size="20" indexed="true"/></td>               
          </tr>
        </logic:iterate>"productList" is defined as an array of Product[], "prod" is defined as a single Product object in the form. But when i run the page, it gives me this errors:
"javax.servlet.jsp.JspException: Cannot create iterator for this collection".
I also tried to make "productList" an ArrayList type, but it game me this same error.
We are using Websphere 4.0 with Struts 1.1.
Anyone can help?
Thanks a lot.
All the best,
warren

Answer 1

Hi , I have similar problem. wonder anyone can help me. I have a datastructure. ArrayList contains list of Hashtable; each Hashtable has two key-value sets ; for each key-value set , value is a ValueObject.
My jsp works ok. but when I click on the radio butten for one radio group, it sets not only the porperty on that row, but the rows belows ,which suppose to be another radio group , because I am using indexed="true". each row should be a individual group seperated by the name poDisplayVO[i] , as show in the html generated .
<!-- JSP -->
<logic:iterate id="poDisplayVO"
name="testForm"
property="poDisplayVOList"
type="java.util.Hashtable">
<tr>
<td>
<bean:write name="poDisplayVO" property="name"/>
</td>
<td>          
<% String val = ((java.util.Hashtable)poDisplayVO).get("subjAreaName").toString();%>
<html:radio indexed="true" name="poDisplayVO" property="fosVO.select" value="<%=val %>" />
<bean:write name="poDisplayVO" property="subjAreaName"/>
</td>
<td>           
<html:radio indexed="true" name="poDisplayVO" property="fosVO.select" value="no" /> NO
</td>
<td>           
<html:radio indexed="true" name="poDisplayVO" property="fosVO.select" value="yes" /> YES
</td>
</tr>
</logic:iterate>
<! ------------------------ html genterated ------------------------------------------------>
the HTML generated as folllows:
<tr>
<td>
          Accounting Studies
</td>
<td>          
     <input type="radio" name="poDisplayVO[0].fosVO.select" value="Accounting">
          Accounting
</td>
<td>           
     <input type="radio" name="poDisplayVO[0].fosVO.select" value="no"> NO
</td>
<td>           
     <input type="radio" name="poDisplayVO[0].fosVO.select" value="yes"> YES
</td>
</tr>
<tr>
<td>
          Accounting Studies
</td>
<td>          
     <input type="radio" name="poDisplayVO[1].fosVO.select" value="Bookkeeping">
          Bookkeeping
</td>
<td>           
     <input type="radio" name="poDisplayVO[1].fosVO.select" value="no"> NO
</td>
<td>           
     <input type="radio" name="poDisplayVO[1].fosVO.select" value="yes"> YES
</td>
</tr>
<tr>
<td>
          Accounting Studies
</td>
<td>          
     <input type="radio" name="poDisplayVO[2].fosVO.select" value="Computerized Accounting(Duplicate)">
          Computerized Accounting(Duplicate)
</td>
<td>           
<input type="radio" name="poDisplayVO[2].fosVO.select" value="no"> NO
</td>
<td>           
<input type="radio" name="poDisplayVO[2].fosVO.select" value="yes"> YES
</td>
</tr>
<! ------------------------ action form-----------------------------------------------
public ArrayList getPoDisplayVOList() {
     return poDisplayVOList;
public void setPoDisplayVOList(ArrayList list) {
     poDisplayVOList = list;
public Hashtable getPoDisplayVO(int i) {
     Object obj = poDisplayVOList.get(i);
     if (obj == null)
          obj = new Hashtable();
          poDisplayVOList.add(obj);
     return (Hashtable)poDisplayVOList.get(i);
public void setPoDisplayVO(Hashtable programDisplayVO, int i) {
          poDisplayVOList.add(i, programDisplayVO);
     }