Hibernate version : 3.0.5

Mapping documents:
<hibernate-mapping package="com.mycode">
<class name="Sequence" table="T_SEQUENCE">
<comment>The sequence table</comment>

<id name="id" column="OBJ_ID" type="integer">
<generator class="native" />
</id>

<version name="versionId" column="VER_ID" type="integer"/>

<property name="objName" column="OBJ_NAME" type="string" />
<property name="sequenceNbr" column="LAST_PRIM_KEY" type="integer" />
</class>
</hibernate-mapping>



I use Struts, Spring, Hibernate with Websphere and MS SQL Server 2000
Code:
I have several unique numbers to be created in different formats. I keep the last number created in the above table. And whenever a new one is required I get the current databse value. Set it in my other domain object which uses it after formatting it and then increment the value in the object and save it. During high loads I get the folowing exception. Let me know what is the best way to resolve this.

Some things I have thought:
Putting this block in synchorized mode -- Problem : it will slow down my applicaiton .
Putting lock in database - problem how to do that in Hibernate.

code snippet,
Sequence userSequence = configService.getSequence( Sequence.USER_ID_SEQUENCE);
domObj.setFormattedUserId("XXXXX"+orderSequence.getSequenceNbr());
userSequence.incrementSequence();
configService.saveSequence(orderSequence);



Exception:
; nested exception is :org.springframework.orm.hibernate3.HibernateOptimisticLockingFailureException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.mmm.ccss.core.config.Sequence#1]; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.mmm.ccss.core.config.Sequence#1]
org.springframework.orm.hibernate3.HibernateOptimisticLockingFailureException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.mmm.ccss.core.config.Sequence#1]; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.mmm.ccss.core.config.Sequence#1]
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.mmm.ccss.core.config.Sequence#1]
at org.hibernate.persister.entity.BasicEntityPersister.check(BasicEntityPersister.java(Compiled Code))
at org.hibernate.persister.entity.BasicEntityPersister.update(BasicEntityPersister.java(Compiled Code))
at org.hibernate.persister.entity.BasicEntityPersister.updateOrInsert(BasicEntityPersister.java(Compiled Code))
at org.hibernate.persister.entity.BasicEntityPersister.update(BasicEntityPersister.java(Compiled Code))
at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java(Compiled Code))
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java(Compiled Code))
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java(Compiled Code))
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java(Inlined Compiled Code))
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java(Compiled Code))
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java(Compiled Code))
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java(Compiled Code))
at org.springframework.orm.hibernate3.HibernateAccessor.flushIfNecessary(HibernateAccessor.java(Compiled Code))
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java(Compiled Code))
at org.springframework.orm.hibernate3.HibernateTemplate.update(HibernateTemplate.java(Inlined Compiled Code))
at org.springframework.orm.hibernate3.HibernateTemplate.update(HibernateTemplate.java(Inlined Compiled Code))
at com.mycode.core.dao.hibernate.ConfigurationDAOImpl.saveSequence(ConfigurationDAOImpl.java(Compiled Code))
at com.mycode.core.service.ConfigurationService.saveSequence(ConfigurationService.java(Inlined Compiled Code))
at com.mmm.ccss.core.service.BaseService.generateOrderId(BaseService.java(Inlined Compiled Code))

Name and version of the database you are using: MS SQL Server 2000