JSF general query regarding UISelectItem and UISelectItems

Question

I am seeing a couple of peculiar behavior and i have no explanation for them at the moment . It would be great if someone can explain the apparently different behavior of JSF in general.
Whenever there is 'n' number of UISelectItem components inside a UISelectOne component , the getter method of the property of the backing bean to which the UISelectOne component's value is bound is getting called "n" number of times when the page is rendered.
Whenever there is a single UISelectItems component inside a parent UIselectOne component , the getter method of the property(in my case a List of SelectItem components) of the backing bean to which the UISelectItems component's value is bound is getting called "2" times when the page is rendered.
The pattern is same for the first time when the page is requested and for any subsequent requests for the page.
What might be the possible reason for the afore mentioned behaviors of JSF?

Answer 1

Getters and setters will be called different times in different Lifecycle phases.
This may help... http://www-128.ibm.com/developerworks/java/library/j-jsf2/
in particular, Select Components have some validation checks that loop over the items in the select component - I believe basically it loops over the selectItems and makes sure the selectItem.value "type" is the same as the selectComponent.value "type"
Also... I just posted this to another thread....
I found adding a Phase Listener with debug logging has helped enourmously with seeing when getter and setters were called in which phase.
public class DebugPhaseListener implements PhaseListener {
    private static final Log LOGGER = LogFactory.getLog(DebugPhaseListener.class);
    public PhaseId getPhaseId() {
        return PhaseId.ANY_PHASE;
    public void beforePhase(PhaseEvent event) {
        LOGGER.debug("beforePhase(" + event.getPhaseId() + ")");
    public void afterPhase(PhaseEvent event) {
        LOGGER.debug("afterPhase(" + event.getPhaseId() + ")");
in your faces-config.xml... add
<lifecycle>
<phase-listener>com.mycompany.DebugPhaseListener</phase-listener>
</lifecycle>