I am struggling with a strange problem. I have two classes, typical many-to-one unidirectional association. Load a child in one session, send the child object together with the parent (no lazy load) to remote clients via RMI. Modify the child on client side and send the child back to server and saveOrUpdate() the child in a new session. I get net.sf.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing:, complaining that the parent object, which just travels with the child to the client side and back without being modified, is transient.
Any idea?

Without any code/mappings it may be difficult...
I assume that you are cascading from child to parent. Is this desired?
What are your unsaved values set to for your identifier?

It is a quite essential 1:n relationship. A partner has n contracts. I just have an unidirectional relationship from contract to partner.


<hibernate-mapping package="com.hdb.model">

<class name="Contract" table="Contract">
<id name="id" column="ID" type="java.lang.Long">
<generator class="sequence">
<param name="sequence">CONTRACT_S</param>
</generator>

</id>

<timestamp name="updateTimestamp" column="UPDATE_TIMESTAMP"></timestamp>
<property name="type" column="TYPE" type="java.lang.Byte" />
......

<many-to-one name="partner" column="PA_ID" class="Partner" cascade="none" />
</class>

</hibernate-mapping>


<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping package="com.hdb.model">

<class name="Partner" table="Partner">
<id name="id" column="ID" type="java.lang.Long">
<generator class="sequence">
<param name="sequence">PArtner_S</param>
</generator>
</id>
<timestamp name="updateTimestamp" column="UPDATE_TIMESTAMP"></timestamp>
<property name="name" column="NAME" type="java.lang.String" not-null="true" />
......
</class>

</hibernate-mapping>


I didn't specified any unsaved-value, which should be null in the default case. I had similar mapping done without problem. But this time, I always run into this TransientObjectException. The programm looks like:
open a session, load a contract and return it, close session. Use the reference returned (which is detached now), change an attribute, open a session, update it, commit, close session. (Everything is fine until now). Use the same reference, change another attribute, open a session, update it, commit and close session. bang, an exception is thrown, complaining that the related partner object is transient.

The situation doesn't change, when I put unsaved-value="null" for the partner object.

Any clue?

I made a small error in my previous problem description. The exception is thrown upone the first update invocation of the detached object.