I have a struts application. When the user requests for Plan information, I use Hibernate to load the object from database and then I fill the values to be displayed to the user. The user modifies these values and then when user sumits the data, I create the object again from scratch with the user values and try to update the database. This operation fails. I get the following exception:

net.sf.hibernate.TransientObjectException: object references an unsaved transien
t instance - save the transient instance before flushing: com.pepsico.mya.bonus.
om.impl.BusinessRuleImpl
at net.sf.hibernate.impl.SessionImpl.throwTransientObjectException(Sessi
onImpl.java:2652)
at net.sf.hibernate.impl.SessionImpl.getEntityIdentifierIfNotUnsaved(Ses
sionImpl.java:2644)
at net.sf.hibernate.type.EntityType.getIdentifier(EntityType.java:66)
at net.sf.hibernate.type.ManyToOneType.nullSafeSet(ManyToOneType.java:46
)
at net.sf.hibernate.persister.EntityPersister.dehydrate(EntityPersister.
java:394)
at net.sf.hibernate.persister.EntityPersister.update(EntityPersister.jav
a:651)
at net.sf.hibernate.persister.EntityPersister.update(EntityPersister.jav
a:625)
at net.sf.hibernate.impl.ScheduledUpdate.execute(ScheduledUpdate.java:52
)
at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2308)
at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2262)
at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2187)
at net.sf.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.j
ava:61)
at com.pepsico.mya.bonus.persistence.PersistenceManagerSupport.save(Pers
istenceManagerSupport.java:218)
at com.pepsico.mya.bonus.persistence.impl.PlanPersistenceManager.save(Pl
anPersistenceManager.java:210)
at com.pepsico.mya.bonus.struts.AbstractSaveAction.execute(AbstractSaveA
ction.java:31)
at org.apache.struts.action.RequestProcessor.processActionPerform(Reques
tProcessor.java:484)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.ja
va:274)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:148
2)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

Your case looks like you are doing these operations in different transactions/sessions.

In a given session if u want to update some object, you either query that
object in that session and update the properties or if you have an object
which was queried in a different session or case like urs, you might have
to associate the object with the second session before you can call update

please show both requests code (of course simplify it before)

And mapping, there is probably a missing cascade attribute somewhere