Greetings,
Mapping file Genre.hbm.xml contains:
<set name="shows" lazy="false" inverse="true" order-by="name">
            <key column="Genre_id"/>
            <one-to-many class="org.springframework.prospring.ticket.domain .Show"/>
        </set>

Since inverse="true" is set up, I expect the bidirectional association from Show to Genre. IMO file Show.hbm.xml should contain something like
<many-to-one name="genre" class="org.springframework.prospring.ticket.domain .Genre"
             column="Genre_id"/>

But Show.hbm.xml has no such stanza.