Hi,
I have got two Entities. Appointment and AppointmentOffer.
The relation is @ManyToMany.
Appointment.java
//bidirektional, inverse Seite
@ManyToMany(fetch=FetchType.EAGER,mappedBy="appointments",cascade=CascadeType.MERGE)
@IndexColumn(name="INDEX_COL")
private List<AppointmentOffer> appointmentOffers= new ArrayList<AppointmentOffer>();
AppointmentOffer.java
//bidirektional, besitzende Seite
@ManyToMany(fetch=FetchType.EAGER)
@IndexColumn(name="INDEX_COL")
private List<Appointment> appointments = new ArrayList<Appointment>();
I have got two jsf-pages. One is first reading the appointmentOffers and then reading the list with appointments from this offers: 
show_appointment_offers.xhtml
<rich:dataTable value="#{appointmentBeanInst.appointmentOffers}" var="appOffer">
<rich:column>
 <h:outputText value="#{appOffer.id}" />
</rich:column>
...
<rich:column>
<h:dataTable value="#{appOffer.appointments}" var="app">
<h:column>
 <h:outputText value="#{app.title}" />
</h:column>
</rich:column>
</rich:dataTable>The second pages tries to do the same with the appointments: 
show_appointments.xhtml 
<rich:dataTable value="#{appointmentBeanInst.freeAppointments}" var="appointment" >
<rich:column sortBy="#{appointment.title}">
 <h:outputText value="#{appointment.title}" />
</rich:column>
...
<rich:column>
<h:dataTable value="#{appointment.appointmentOffers}" var="appOffer">
<h:column>
 <h:outputText value="#{appOffer.title}" />
</h:column>
</h:dataTable>
...
The problem is that in the second page only one of the appointmentOffers is shown (in the list is only one appointmentOffer). I do not understand this. The only difference between the first and the second page is that appointmentOffer is the owner side. Is that the reason? How can I solve this? 
Thanks for your hints. 
NSchweig