How to set the default value of Selectonemenu Jsf Primefaces

This is an example to set the default value of Selectonemenu in Jsf Primefaces :

we have a user that we need change his group from a list of groups.


User.group : Administrateur

Application.groups : {Administrator,Moderator,guest}

<p:selectOneMenu value="#{User.group}">  
<f:selectItems value="#{Application.groups}" />  
</p:selectOneMenu>

The Result :