Hi,
We are using HIbernate 3.3.2 provided JPA 1.0 in our application along with JBPM 4.x and spring 3.x.
The integration is working quite fine but only concern is the high CPU usage.

When we took the heap dumps we noticed the following objects to be taking maximum amount of memory.
1) org/hibernate/ejb/EntityManagerFactoryImpl --> total size 607 MB
2) org/hibernate/imp/SessionFactoryImpl --> total size 607 MB
3) org/hibernate/persister/collection/OneToManyPersister --> total size 19 MB.
4) org/springframework/orm/jpa/LocalContainerEntityManagerFactoryBean

We also noticed that when we did JBPM integration we started facing this issue.
Below are the configuration settings which we did for JBPM in spring configuration file.

- <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
- <property name="mappingResources">
- <list>
<value>jbpm.repository.hbm.xml</value>
<value>jbpm.execution.hbm.xml</value>
<value>jbpm.history.hbm.xml</value>
<value>jbpm.task.hbm.xml</value>
<value>jbpm.identity.hbm.xml</value>
</list>
</property>
- <!--

Hibernate properties needed to configure the session factory to use JTA.
This will ensure that jBPM can participate in the application's JTA transactions.


-->
- <property name="hibernateProperties">
- <props>
<prop key="hibernate.transaction.factory_class">org.hibernate.transaction.CMTTransactionFactory</prop>
<prop key="hibernate.transaction.manager_lookup_class">org.hibernate.transaction.WebSphereTransactionManagerLookup</prop>
<prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>
<prop key="hibernate.connection.datasource">java:jdbc/naps_dataSource1.1</prop>
<prop key="jta.UserTransaction">java:comp/UserTransaction</prop>
<prop key="hibernate.hbm2ddl.auto">false</prop>
</props>
</property>
</bean>

our persistence.xml file entires are like this
------------------------------------------
<persistence-unit name="NAPS_JPA" transaction-type="JTA">
<provider>org.hibernate.ejb.HibernatePersistence</provider>

<!-- HIBERNATE properties
-->
- <properties>
- <!-- Hibernate Configuration Properties
-->
<property name="hibernate.archive.autodetection" value="class, hbm" />

-->
<property name="hibernate.dialect" value="org.hibernate.dialect.SQLServerDialect" />

-->
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.format_sql" value="true" />
<property name="hibernate.use_sql_comments" value="true" />
<property name="hibernate.default_batch_fetch_size" value="25" />
<property name="hibernate.order_updates" value="true" />
<property name="hibernate.generate_statistics" value="true" />
- <!-- Hibernate Transaction Properties
-->
<property name="hibernate.transaction.factory_class" value="org.hibernate.transaction.CMTTransactionFactory" />
<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.WebSphereTransactionManagerLookup" />
<property name="hibernate.transaction.auto_close_session" value="false" />
<property name="hibernate.transaction.flush_before_completion" value="false" />
<property name="hibernate.current_session_context_class" value="org.hibernate.context.JTASessionContext" />
<property name="jta.UserTransaction" value="java:comp/UserTransaction" />
<property name="databasePlatform" value="org.hibernate.dialect.SQLServerDialect" />
- <!-- Hibernate Cache Properties
-->
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider" />
<property name="hibernate.cache.use_query_cache" value="false" />
<property name="hibernate.cache.use_second_level_cache" value="false" />

Can you please let us know what is causing so much memory hike.
Actually this is happening during EAR deployment only.

Can anyone provide any pointers on this?

maybe this can help u: viewtopic.php?f=1&t=981076
I think your hibernate.default_batch_fetch_size property is too great. Hibernate holds in memory a lot of SQL string (one for each access mode) and combined with default_batch_fetch_size it takes a plenty of memory!