Unable to persist object : detached entity passed to persist - jpa

Question

I am using JSF - EJB3 - Hibernate JPA2.0 in my application. In one of the screens when I try to persist a new entry, I get the following exception:
Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist: info.novatec.timemgmt.entities.Customer
Following are chunks of my code that may be helpful,
View:
<h:form>
<h:panelGrid columns="2">
<h:outputLabel value="Customer:" for="customer" />
<h:selectOneMenu id="customer" value="#{projectController.selected.customer}" title="Customer" >
<f:selectItems value="#{customerController.itemsAvailableSelectOne}"/>
</h:selectOneMenu>
<h:outputLabel value="Name:" for="name" />
<h:inputText id="name" value="#{projectController.selected.name}" title="Name" />
<p:calendar id="endDate" value="#{projectController.selected.endDate}" showOn="button" pattern="MM/dd/yyyy" size="10"/>
</h:panelGrid>
Managed bean
#ManagedBean
#SessionScoped
public class CustomerController implements Serializable {
// ...
public SelectItem[] getItemsAvailableSelectOne() {
return JsfUtil.getSelectItems(ejbFacade.findAll(), true);
}
// ...
}
JSFUtil helper class:
public class JsfUtil{
public static SelectItem[] getSelectItems(List<?> entities, boolean selectOne) {
int size = selectOne ? entities.size() + 1 : entities.size();
SelectItem[] items = new SelectItem[size];
int i = 0;
if (selectOne) {
items[0] = new SelectItem("", "---");
i++;
}
for (Object x : entities) {
items[i++] = new SelectItem(x, x.toString());
}
return items;
}
}
Could you please point as to where I am going wrong?

Answer 1

The problem is in your Converter for the Customer class (which you omitted from the question, but it's surely there in your real code). You seem to be manually constructing a new Customer() with an ID instead of obtaining the Customer instance from entity manager by its ID. Fix the converter accordingly.