<class name="User" table="user">
        <id name="id" type="int">
            <column name="userid" />
            <generator class="assigned" />
        </id>
        <property name="name" type="string">
            <column name="username" />
        </property>
   <set name="relationships" table="relationship" inverse="false" cascade="none" lazy="true">
       <key column="personid"/>
       <many-to-many column="relationid " class="User"/>
   </set>
     </class>

User {
   private int id;
   private String name;
   private Collection<User> relationships;
}