Please specify more clear how you reproduce this problem by using the JSF Pages from Entity Class.

1/ Created a Java Class Library project with two entities in @OneToMany relationship - Pytanie and Odpowiedz. Pytanie
had odpowiedzi persistent attribute of type java.util.List<Odpowiedz>
2/ Created a Web Application project of which the Java Class Library with the entities was a dependency (library)
3/ Upon executing the wizard the New.jsp page for Pytanie had not the persistent property and that's the exception all
about.

Yes, please attach to project. Thanks.

The project with 2 entities in @OneToMany relationship and the other - web application project are at
http://www.jaceklaskowski.pl/aplikacje/pio-netbeansprojects.zip. They worked fine as I'd manually added the missing
property - odpowiedziOfPytanie - to the backing bean - pioweb.PytanieController. Remove the property and you'll see the
issue.

I notice this application was generated with out-of-date netbeans code. You may want to try generating the application
from the entities again, using current netbeans code.

I tried with current netbeans code; that was not the problem. But I do think I see the cause. Odpowiedz does not have a
property of type Pytanie with an appropriate @ManyToOne annotation.

Here is an example that appears in the JPA specification:

Example 1: One-to-Many association using generics
In Customer class:
@OneToMany(cascade=ALL, mappedBy=”customer”)
public Set<Order> getOrders() { return orders; }
In Order class:
@ManyToOne
@JoinColumn(name="CUST_ID", nullable=false)
public Customer getCustomer() { return customer; }