<class name="ProjectItem" table="LM_PROJECT_ITEM" polymorphism="explicit">

        <id name="id" column="M_ID" >
         <generator class="uuid"/>
      </id>

        <property name="name" column="M_NAME" not-null="true"/>
        <property name="description" column="M_DESCRIPTION" not-null="true"/>
        <property name="date" column="M_CREATION_DATE" type="date"/>
        <property name="parentId" column="M_PARENT_ID" />

        <bag name="childs">
            <key column="M_PARENT_ID"/>
            <one-to-many class="com.asv.sdi.lm.model.ProjectItem"/>
        </bag>

        <join table="LM_EX_PROJECT_ITEM" optional="true" inverse="true">
            <key column="EX_ID"/>
            <property name="fk" column="EX_ID" insert="false" update="false"/>
            <property name="howToTest" column="M_HOW_TO_TEST"/>
            <property name="importance" column="M_IMPORTANCE"/>
            <property name="initialEstimate" column="M_INITIAL_ESTIMATE"/>
            <property name="realEstimate" column="M_REAL_ESTIMATE"/>
            <property name="progress" column="M_PROGRESS"/>
        </join>

   </class>

public List getRootProjectItems() {
        List items = getHibernateTemplate().find("from ProjectItem as pi left outer join fetch pi.childs where pi.parentId is null ");
        return items;
    }

public List getRootProjectItems() {
        List items = getHibernateTemplate().find("from ProjectItem as pi where pi.parentId is null ");
        if (items != null) {
            Iterator it = items.iterator();
            while (it.hasNext()) {
                ProjectItem projectItem = (ProjectItem) it.next();
                getHibernateTemplate().initialize(projectItem.getChilds());
            }
        }
        return items;
    }

   <set name="childs">
            <key column="M_PARENT_ID"/>
            <one-to-many class="com.asv.sdi.lm.model.ProjectItem"/>
        </set>

public void testAllItems() {
        List rootProjectItems = projectItemDAO.getRootProjectItems();
        for (int i = 0; i < rootProjectItems.size(); i++) {
            ProjectItem projectItem = (ProjectItem) rootProjectItems.get(i);
            BigDecimal initialEstimate = projectItem.getInitialEstimate();
            showCurrentHierarchyLevel(projectItem.getChilds());
        }
    }

    private void showCurrentHierarchyLevel(Collection childs) {
        Iterator it = childs.iterator();
        while (it.hasNext()) {
            ProjectItem projectItem = (ProjectItem) it.next();
            if (projectItem.getChilds() != null) {
                showCurrentHierarchyLevel(projectItem.getChilds());
            }
        }
    }