how to use lazy loading, not putting business logic in the getter - jsf

Question

i learned through searching that i shouldn't be putting the business logic in the getters but i really dont know how to fix it. I read Why JSF calls getters multiple timesand i used but i still dont get the result that i want .
<h:form id="form">
<h:panelGrid columns="2" cellpadding="5">
<h:outputText value="Nom personnel : " style="font-size: 18px" />
<p:selectOneMenu value="#{personnelBean.nom}" >
<f:selectItem itemValue="#{null}" itemLabel="--Séléctionner Nom" />
<f:selectItems value="#{personnelBean.listePersonnels}" var="personnel"
itemValue="#{personnel.nom}" itemLabel="#{personnel.nom}" />
<f:ajax listener="#{personnelBean.submit()}" render="display"/>
</p:selectOneMenu>
</h:panelGrid>
<h:panelGrid columns="2" cellpadding="5">
<h:outputText value="Prénom personnel : " style="font-size: 18px" />
<p:selectOneMenu value="#{personnel1Bean.cin}" id="display" >
<f:selectItem itemValue="#{null}" itemLabel="--Séléctionner Nom" />
<f:selectItems value="#{personnel1Bean.listePersonnels}" var="personnel"
itemValue="#{personnel.cin}" itemLabel="#{personnel.prenom}" />
<f:ajax listener="#{personnel1Bean.submit()}" render="dis"/>
</p:selectOneMenu>
</h:panelGrid>
<h:outputText value="Nombre d'enfants : "/>
<h:outputText id="dis" value="#{personnel1Bean.nombreEnfants}" />
</h:form>
Personnel1Bean.java
private Integer loadNombreEnfants() {
String cin = submit();
System.out.println("CIN" + cin);
Personnel p = personnelMetier.getPersonnel(cin);
nombreEnfants = p.getNombreEnfants();
System.out.println(nombreEnfants);
return nombreEnfants;
}
public Integer getNombreEnfants() {
return nombreEnfants;
}
public void ajaxListener(AjaxBehaviorEvent event) {
nombreEnfants = loadNombreEnfants();
}