JSF & Webflow - <h:selectManyListbox> converting troubles

In JSF, I have this:

<h:selectManyListbox id="createAccountBasicInfo_select_Types"
 styleClass="selectManyCheckbox" value="#{party.roles}" size="6"
 converter="persistenceObjectToStringTwoWayConverter">
      <f:selectItems value="#{accTypes.selectItems}" />
</h:selectManyListbox>

My Converter:

 //[...]
 import javax.faces.convert.Converter;
 //[...]

public class PersistenceObjectToStringJSFConverter implements Converter {
    //[...]

public Object getAsObject(FacesContext context, UIComponent component, String value) {
    Long id = Long.valueOf(value);
    Object object = null;
    try {
        object = getPersistenceService(context).loadByEntityId(id); // here I load the appropriate record
    } catch (CoreException e) {
        e.printStackTrace();
    } catch (ElementCreationException e) {
        e.printStackTrace();
    }
    return object; //here I need to return an ArrayList of the loaded Objects instead of a single object
}
 }

In HTML, I get this:

<select id="form_party:createAccountBasicInfo_select_Types"
 name="form_party:createAccountBasicInfo_select_Types" class="selectManyCheckbox" 
 multiple="multiple" size="6"> 
  <op开发者_如何转开发tion value="171128">Andere</option>
  <option value="171133">Interessent</option>
  <option value="171130">Kunde</option>
  <option value="171131">Lieferant</option>
  <option value="171134">Mitarbeiter</option>
  <option value="171132">Mitbewerber</option>
  <option value="171129">Partner</option>
</select>

The value of each option is an Id, which I have to load from the database. An ArrayList of the selected entries will then be given to the WebFlow and then saved to the database.

When I press my "save" button, the selected items run through a Converter, where I need to load the items from the database (by value, ex. "171128") and add it to an ArrayList, which will be inserted into "party.roles" (check JSF Code).

My problem: I'm getting the following JSF Exception:

/WEB-INF/page/core/fragments/account/accountBasicInfo.xhtml @152,58 value="#{party.roles}": Property 'roles' not writable on type java.util.List

I think there is a problem with my Converter. What do I have to change?

Thank's for you anwsers!

(I'm using JSF 1.2)

The exception is telling that #{party} is actually a java.util.List which in turn indeed doesn't have a setRoles() method so the #{party.roles} ain't going to work.

The #{party} should be a managed bean and it should have a private List<Role> roles property with a getter. The converter should not return a List<Role> on the getAsObject() but it should return Role.