from Order o left join fetch o.items i join fetch i.product

select o from Order o left join fetch o.items i join fetch i.product

Exception in thread "main" org.hibernate.QueryException: query specified join fetching, but the owner of the fetched association was not present in the select list [FromElement{explicit,not a collection join,fetch join,fetch non-lazy properties,classAlias=null,role=null,tableName=Product,tableAlias=product2_,origin=items items1_,colums={items1_.p_id ,className=lab3.Product}}] [select o from lab3.Order o left join fetch o.items i join fetch i.product]
   at org.hibernate.hql.ast.tree.SelectClause.initializeExplicitSelectClause(SelectClause.java:217)
   at org.hibernate.hql.ast.HqlSqlWalker.useSelectClause(HqlSqlWalker.java:727)
   at org.hibernate.hql.ast.HqlSqlWalker.processQuery(HqlSqlWalker.java:551)
   at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:645)
   at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:281)
   at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:229)
   at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:251)
   at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:183)
   at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:134)
   at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101)
   at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80)
   at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:94)
   at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:156)
   at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:135)
   at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1650)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:597)
   at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:342)
   at $Proxy0.createQuery(Unknown Source)
   at lab3.OnlineStoreApp.run(OnlineStoreApp.java:32)
   at lab3.OnlineStoreApp.main(OnlineStoreApp.java:14)

package lab3;

import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class OnlineStoreApp {
   private SessionFactory factory;
   private Session session;

   public static void main(String[] args) {
      new OnlineStoreApp().run();
   }

   public OnlineStoreApp() {
      Configuration cfg = new Configuration();
      cfg.configure();
      factory = cfg.buildSessionFactory();
   }

   @SuppressWarnings("unchecked")
   private void run() {
      session = factory.getCurrentSession();
      session.beginTransaction();
      Order o = new Order();
      o.getItems().add(new OrderItem(new Product("p1"), 10));
      o.getItems().add(new OrderItem(new Product("p2"), 20));
      session.save(o);
      List<Order> orders = session
            .createQuery(
                  "select o from Order o left join fetch o.items i join fetch i.product")
            .list();
      System.out.println(orders.size());
      session.getTransaction().commit();
   }

}

package lab3;

import java.util.ArrayList;
import java.util.List;

public class Order {
   private Long internalId;
   private List<OrderItem> items;

   public Order() {
      items = new ArrayList<OrderItem>();
   }

   public Long getInternalId() {
      return internalId;
   }

   public void setInternalId(Long internalId) {
      this.internalId = internalId;
   }

   public List<OrderItem> getItems() {
      return items;
   }

   public void setItems(List<OrderItem> items) {
      this.items = items;
   }

}

package lab3;

public class OrderItem {
   private Product product;
   private int qty;

   public OrderItem() {
   }

   public OrderItem(Product product, int qty) {
      this();
      this.product = product;
      this.qty = qty;
   }

   public Product getProduct() {
      return product;
   }

   public void setProduct(Product product) {
      this.product = product;
   }

   public int getQty() {
      return qty;
   }

   public void setQty(int qty) {
      this.qty = qty;
   }


}

package lab3;


public class Product {
   private Long internalId;
   private String name;

   public Product() {
   }

   public Product(String name) {
      this();
      this.name = name;
   }

   public Long getInternalId() {
      return internalId;
   }

   public void setInternalId(Long internalId) {
      this.internalId = internalId;
   }

   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }


}

<?xml version="1.0"?>
<!DOCTYPE hibernate-configuration PUBLIC
   "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
   "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
   <session-factory>
      <property name="hibernate.connection.url">jdbc:h2:tcp://localhost/~/test</property>
      <property name="hibernate.connection.driver_class">org.h2.Driver</property>
      <property name="hibernate.connection.username">sa</property>
      <property name="hibernate.connection.password"></property>
      <property name="hibernate.hbm2ddl.auto">update</property>
      <property name="hibernate.dialect">org.hibernate.dialect.H2Dialect</property>
      <property name="hibernate.current_session_context_class">thread</property>
      <property name="hibernate.show_sql">false</property>
      <mapping resource="Product.hbm.xml"/>
      <mapping resource="Order.hbm.xml"/>
   </session-factory>
</hibernate-configuration>    

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
   <class name="lab3.Order" table="orders">
      <id name="internalId">
         <generator class="sequence"></generator>
      </id>
      <list name="items" cascade="save-update">
         <key column="o_id"></key>
         <list-index column="idx"></list-index>
         <composite-element class="lab3.OrderItem">
            <many-to-one name="product" column="p_id" cascade="save-update"></many-to-one>
            <property name="qty"></property>
         </composite-element>
      </list>
   </class>
</hibernate-mapping>

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
   <class name="lab3.Product">
      <id name="internalId">
         <generator class="sequence"></generator>
      </id>
      <property name="name"></property>
   </class>
</hibernate-mapping>