Omnnifaces

xmlns:o="http://omnifaces.org/ui"
xmlns:of="http://omnifaces.org/functions"

<h:selectOneMenu value="#{bean.selectedItem}" converter="omnifaces.SelectItemsConverter">
    <f:selectItems value="#{bean.availableItems}" />
</h:selectOneMenu>

 <h:outputLabel for="iterator" value="Items with iterator: " />
        <h:selectOneMenu id="iterator" value="#{selectItemsBean.selectedEntity}" converter="omnifaces.SelectItemsIndexConverter">
            <f:selectItem itemValue="#{null}" itemLabel="Choose item" noSelectionOption="true" />
            <f:selectItems value="#{selectItemsBean.exampleEntities}" var="entity" itemLabel="#{entity.value}" itemValue="#{entity}" />
            <f:ajax render="selected_item" />
      </h:selectOneMenu>