This is the problem. I have two entities: Profile and User.
1 user has many profiles
But 1 user also has an "active profile". An active profile is the profile this user is currently using.

Table USER:

USER_ID: VARCHAR(10)
NAME: VARCHAR(20)
EMAIL: VARCHAR(20)
SERIAL_NUMBER:VARCHAR(20)
PROFILE_ID: INTEGER (this is the foreign key that references the active profile)

Table PROFILE:

PROFILE_ID: INTEGER
NAME: VARCHAR_20
USER_ID: VARCHAR(10) (This is the Foreign Key that indicutes whose profile is this).

My Classes:
public class User {
private String userID;

private String name;

private String email;

private String serialNumber;

private List profiles;

private Profile activeProfile;
//getters, setters, etc...
}

public class Profile {

private int profileID;

private String name;

//getters, setters, etc...
}

The problem is: After I mapped the activeProfile in the user.hbm.xml I get NullPointerExceptions when I try to retrieve Users that actually have an active profile setted. This error does not occur when I try to retrieve users that do not have active profiles set (Their PROFILE_ID column is null).

Can anyone here please help me?

Here are my .hbm.xml files:

<hibernate-mapping>

<class name=User"
table="USER" >

<id name="userID" column="USER_ID"/>

<property name="name" column="NAME" />
<property name="email" column="EMAIL" />
<property name="serialNumber" column="SERIAL_NUMBER" />

<!--<many-to-one name="activeProfile" column="ACTIVE_PROFILE"
class="Profile"
cascade="all"/>-->

<many-to-one name="activeProfile"
class="com.ibm.extremeblue.callhandling.entities.Profile"
column="PROFILE_ID" insert="false" update="true"/>

<bag name="profiles" table="PROFILE" cascade="all">
<key column="USER_ID" />
<one-to-many class="Profile"/>
</bag>

</class>

</hibernate-mapping>

<hibernate-mapping>

<class name="Profile" table="PROFILE">

<id name="profileID" column="PROFILE_ID">
<generator class="identity" />
</id>

<property name="name" column="NAME" />

</class>

</hibernate-mapping>

The exception stack trace is:

Exception in thread "main" java.lang.NullPointerException
at org.hibernate.tuple.AbstractEntityTuplizer.createProxy(AbstractEntityTuplizer.java:372)
at org.hibernate.persister.entity.AbstractEntityPersister.createProxy(AbstractEntityPersister.java:3121)
at org.hibernate.event.def.DefaultLoadEventListener.createProxyIfNecessary(DefaultLoadEventListener.java:232)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:173)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:87)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:862)
at org.hibernate.impl.SessionImpl.internalLoad(SessionImpl.java:830)
at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:266)
at org.hibernate.type.EntityType.resolve(EntityType.java:303)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:116)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:842)
at org.hibernate.loader.Loader.doQuery(Loader.java:717)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1785)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:47)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:41)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2730)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:177)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:87)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:862)
at org.hibernate.impl.SessionImpl.get(SessionImpl.java:799)
at org.hibernate.impl.SessionImpl.get(SessionImpl.java:792)
at com.ibm.extremeblue.callhandling.persistence.UserDAO.loadUser(UserDAO.java:19)
at com.ibm.extremeblue.callhandling.persistence.UserDAO.main(UserDAO.java:41)

Hibernate version:
3.2

Mapping documents:

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:

Name and version of the database you are using:

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:


Problems with Session and transaction handling?

Read this: http://hibernate.org/42.html

you did a mistake!!!!!!!!!!

Ur user table has a foreign key to profile table, simultaneously
ur profile table has a foreign key to user table.

[color=darkred][u][i][b]HOW COULD IT BE?[/b][/i][/u][/color]

Make profiles independant of user.
An user may have multiple profile, store them in Set for the java class
with one active_profile number.

That's it.

I didn't understand your solution.
The foreign key the user has to profile indicates which profile is that user's active profile.
How should the tables be then?

Thanks for your help!