Class Company has a many-to-one relationship to Person (chief) which has a set of composite-elements (addresses). The Line:
Session.createQuery(
"from Company c
join fetch c.owner o
join fetch o.addresses a")
produces a Nullpointer Exception.

Here is my test code (tested with hibernate-core-3.3.0.SP1):


Configuration cfg =
new Configuration().addDirectory(new File("src/main/java/org/donmiguel"));

Properties p = new Properties();
p.setProperty("hibernate.dialect", "org.hibernate.dialect.HSQLDialect");
p.setProperty("hibernate.connection.driver_class", "org.hsqldb.jdbcDriver");
p.setProperty("hibernate.hbm2ddl.auto", "create-drop");
p.setProperty("hibernate.connection.username", "sa");
p.setProperty("hibernate.connection.password", "");
p.setProperty("hibernate.connection.url", "jdbc:hsqldb:file:testdb");
p.setProperty("hibernate.show_sql", "true");
p.setProperty("hibernate.format_sql", "true");
cfg.setProperties(p);
SessionFactory sessionFactory = cfg.buildSessionFactory();

Session session = sessionFactory.openSession();
Query query = session.createQuery(//
"from Company c " //
+ "join fetch c.owner o " //
+ "join fetch o.addresses a"//
);

Here is the occuring Exception:

java.lang.NullPointerException
at org.hibernate.loader.BasicLoader.isBag(BasicLoader.java:94)
at org.hibernate.loader.BasicLoader.postInstantiate(BasicLoader.java:76)
at org.hibernate.loader.hql.QueryLoader.<init>(QueryLoader.java:119)
at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:204)
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 org.donmiguel.TestHibernate.test(TestHibernate.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)

And here are my classes:

public class Company {
private Long id;
private Person owner;

public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Person getOwner() {
return owner;
}
public void setOwner(Person owner) {
this.owner = owner;
}
}

<?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 package="org.donmiguel">
<class name="Company">
<id name="id">
<generator class="native" />
</id>
<many-to-one name="owner"/>
</class>
</hibernate-mapping>

public class Person {
private Long id;
private Set<Address> addresses;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Set<Address> getAddresses() {
return addresses;
}
public void setAddresses(Set<Address> addresses) {
this.addresses = addresses;
}
}

<?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 package="org.donmiguel">
<class name="Person">
<id name="id">
<generator class="native" />
</id>
<set name="addresses">
<key column="person_id" />
<composite-element class="Address">
<property name="country" />
<property name="street" />
</composite-element>
</set>
</class>
</hibernate-mapping>


public class Address {
private String street;
private String country;
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
}


Please, could anyone tell me, if I'm doing something wrong? Is the mapping incorrect? Any comments are welcome.