I am still a newbie attempting to get the Cat example program running with an Oracle9i database.

The following code:

// Initialize Hibernate (Configuration and SessionFactory)
initHibernate();

// Prepare out
response.setContentType("text/html");
PrintWriter out = response.getWriter();

// Create some Cats
beginTransaction();
createCats(out);
endTransaction(true);

public void createCats(PrintWriter out)
throws HibernateException {


Cat princess = new Cat();
princess.setType('W');
princess.setSex('F');
princess.setWeight(7.4f);
session.save(princess);

Cat max = new Cat();
max.setType('D');
max.setSex('M');
max.setWeight(8.1f);
session.save(max);

Cat sophie = new Cat();
sophie.setType('D');
sophie.setSex('F');
sophie.setWeight(4.1f);
session.save(sophie);
}

private void initHibernate()
throws HibernateException {

// Load Configuration and build SessionFactory
sessionFactory = new Configuration().configure().buildSessionFactory();
}

private void beginTransaction()
throws HibernateException {

session = sessionFactory.openSession();
transaction = session.beginTransaction();
}

private void endTransaction(boolean commit)
throws HibernateException {

if (commit) {
transaction.commit(); <==== Exception occurs here
} else {
// Don't commit the transaction, can be faster for read-only operations
transaction.rollback();
}
session.close();
}

==========================================

public class Cat {

private long id;
private String color;
private char sex, type;
private float weight;

public Cat() {
}

public long getId() {
return id;
}

public void setId(long id) {
this.id = id;
}

==========================================

<hibernate-mapping>

<class name="ex.Cat" table="CATS" discriminator-value="W">
<id name="id" column="id" type="int">
<generator class="sequence">
<param name="sequence">id_seq</param>
</generator>
</id>

<discriminator column="type" type="character"/>

<property name="color" not-null="true"/>
<property name="sex" not-null="true" update="false"/>
<property name="weight"/>

<subclass name="ex.DomesticCat" discriminator-value="D">
<property name="name" column="name" type="string"/>
</subclass>
</class>

==========================================

SQL> desc cats;
Name Null? Type
----------------------------------------- -------- ------------------
ID NOT NULL NUMBER(1)
SEX NOT NULL NUMBER(1)
WEIGHT NOT NULL NUMBER(1)
NAME VARCHAR2(30)

SQL> select * from user_sequences;

SEQUENCE_NAME MIN_VALUE MAX_VALUE INCREMENT_BY C O CACHE_SIZE
------------------------------ ---------- ---------- ------------ - - ----------
LAST_NUMBER
-----------
ID_SEQ 1 1.0000E+27 1 N N 20
41
==========================================

Generates this exception:

net.sf.hibernate.HibernateException: identifier of an instance of ex.Cat altered from 16 to 16

void net.sf.hibernate.impl.SessionImpl.flushEntities()

SessionImpl.java:2141

void net.sf.hibernate.impl.SessionImpl.flushEverything()

SessionImpl.java:2017

void net.sf.hibernate.impl.SessionImpl.flush()

SessionImpl.java:2004

void net.sf.hibernate.transaction.JDBCTransaction.commit()

JDBCTransaction.java:57

void ex.TestServlet.endTransaction(boolean)

TestServlet.java:131

I looked through the source code in SessionImpl.java and I am not sure why this is going off

if ( !entry.id.equals(oid) ) throw new HibernateException(
"identifier of an instance of " +
persister.getClassName() +
" altered from " +
entry.id +
" to " + oid
);

Since the value is 16 in both cases

Thanks, pugmaster

You've mapped a long as type="int".


instanes of Long are never equal() to an Integer :)


good luck!

I'm getting the same exception only the numbers are different
identifier of an instance of com.resqsoft.db.hibernate.JobCandidateHb altered from 410 to 411. The class and mapping file are both a long. What could be the cause of this?

Thanks for any help,
Jeff Cooper

you changed an identifier value