Using Hibernate + annotations, I'm trying to do the following:

Two entities, Entity1 and Entity2.

• Entity1 contains a simple generated value primary key.
• Entity2 primary key is composed by a simple generated value + the id of entity one (with a many to one relationship)

Unfortunately, I can't make it work.

Here is an excerpt of the code:

@Entity
public class Entity1 {

 @Id @GeneratedValue
 private Long id;

 private String name;

    ...
}

@Entity
public class Entity2 {

 @EmbeddedId
 private Entity2PK pk = new Entity2PK();

 private String miscData;

    ...
}

@Embeddable
public class Entity2PK implements Serializable {

 @GeneratedValue
 private Long id;

 @ManyToOne
 private Entity1 entity;
}

void test() {

    Entity1 e1 = new Entity1();
    e1.setName("nameE1");
    Entity2 e2 = new Entity2();

    e2.setEntity1(e1);
    e2.setMiscData("test");

    Transaction transaction = session.getTransaction();
    try {
     transaction.begin();

     session.save(e1);
     session.save(e2);

     transaction.commit();
    } catch (Exception e) {
     transaction.rollback();
    } finally {
     session.close();
    }
}

When I run the test method I get the following errors:

Hibernate: insert into Entity1 (id, name) values (null, ?)
Hibernate: call identity()
Hibernate: insert into Entity2 (miscData, entity_id, id) values (?, ?, ?)
07-Jun-2010 10:51:11 org.hibernate.util.JDBCExceptionReporter logExceptions
WARNING: SQL Error: 0, SQLState: null
07-Jun-2010 10:51:11 org.hibernate.util.JDBCExceptionReporter logExceptions
SEVERE: failed batch
07-Jun-2010 10:51:11 org.hibernate.event.def.AbstractFlushingEventListener performExecutions
SEVERE: Could not synchronize database state with session
org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update
 at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
 at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
 at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
 at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:254)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266)
 at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167)
 at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
 at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
 at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1001)
 at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:339)
 at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
 at test.App.main(App.java:32)
Caused by: java.sql.BatchUpdateException: failed batch
 at org.hsqldb.jdbc.jdbcStatement.executeBatch(Unknown Source)
 at org.hsqldb.jdbc.jdbcPreparedStatement.executeBatch(Unknown Source)
 at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
 at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:247)
 ... 8 more

Note that I use HSQLDB.

Any ideas about what is wrong ?