h:selectManyListBox setter not setting all the values selected - jsf

Question

<h:selectManyListbox id="sectorsListBox" size="2" multiple="multiple" value="#{Mybean.classificationSelectedItems}">
<f:selectItems id="sectors" value="#{Mybean.classificationSelectItems}"/>
</h:selectManyListbox>
Backing Bean has:
public class Mybean
{
private Map<String,String> classificationSelectItems = new LinkedHashMap<String,String>();
private List<String> classificationSelectedItems = new ArrayList<String>();
//getter and setter for both.
}
init()
{
classificationSelectItems.put("INS","Insurance")
classificationSelectItems.put("HLC","HealthCare")
}
The select many box gets initialized with these 2 values but the problem is only the last selected entry is getting stored in classificationSelectedItems. Why is that so ? And how do I get all the selected entries stored in the list of classificationSelectedItems ?
Adding FYI, the init method is class by Spring.

Answer 1

I have tested with an examle(reference:http://www.mkyong.com/jsf2/jsf-2-multiple-select-listbox-example/), good luck :)
Facelets:
<h:form id="form">
<h:selectManyListbox value="#{user.favFood1}" >
<f:selectItems value="#{user.favFood2Value}" />
</h:selectManyListbox>
<h:commandButton value="test"/>
</h:form>
Bean:
#ManagedBean(name = "user")
#ViewScoped
public class UserBean implements Serializable {
private static final long serialVersionUID = 1L;
public List<String> favFood1;
private Map<String, Object> food2Value;
public UserBean() {
favFood1 = new ArrayList<String>();
food2Value = new LinkedHashMap<String, Object>();
food2Value.put("Food2 - Fry Checken", "Fry Checken1"); //label, value
food2Value.put("Food2 - Tomyam Soup", "Tomyam Soup2");
food2Value.put("Food2 - Mixed Rice", "Mixed Rice3");
}
public List<String> getFavFood1() {
return favFood1;
}
public void setFavFood1(List<String> favFood1) {
this.favFood1 = favFood1;
}
public Map<String, Object> getFavFood2Value() {
return food2Value;
}
}

Answer 2

I noticed exactly this behaviour when I used a Collection in the setter method, like
public void setClassificationSelectedItems(Collection<String> in){
// store it somewhere
}
This setter is called during the restore phase but not during the update phase, so the previously set value will be set, but never the new one. If you use a List, it works as expected:
public void setClassificationSelectedItems(List<String> in){
// store it somewhere
}
Note that you will need to redeploy the application after such a change because the JSP needs to be recompiled but this isn’t done automatically.