I am getting this exception when trying to run a select query.

Java version: 1.4.2_04
Hibernate version:2.7
DB: oracle
OS: windows.

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

<class name="proj.Prod" table="product">

<id name="Id" type="long" unsaved-value="null" >
<column name="Id" sql-type="number" not-null="true"/>
<generator class="sequence">
<param name="sequence">SEQ_PROD</param>
</generator>
</id>

<map name="units"
table="prod_units"
schema="prod"
lazy="false"
cascade="delete"
sort="unsorted"
order-by="unitid asc"
outer-join="auto"
access="field">
<key column="prodid"/>
<index column="prodId" type="long"/>
<element column="unitId" type="proj.Unit"/>
</map>

</class>

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

<hibernate-mapping>

<class name="proj.Unit" table="prod_units">
<id name="unitId" type="long" unsaved-value="null" >
<column name="unitId" sql-type="long" not-null="true"/>
<generator class="sequence">
<param name="sequence">SEQ_UNIT</param>
</generator>
</id>

<property name="Id"/>


</class>

</hibernate-mapping>


I know there is a simple answer to this question. I quess the problem is in my collection mapping.

Thanks for any help.

net.sf.hibernate.type.SerializationException: could not deserialize
at net.sf.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:211)
at net.sf.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:234)
at net.sf.hibernate.type.SerializableType.fromBytes(SerializableType.java:73)
at net.sf.hibernate.type.SerializableType.get(SerializableType.java:38)
at net.sf.hibernate.type.NullableType.nullSafeGet(NullableType.java:62)
at net.sf.hibernate.type.NullableType.nullSafeGet(NullableType.java:53)
at net.sf.hibernate.collection.AbstractCollectionPersister.readElement(AbstractCollectionPersister.java:365)
at net.sf.hibernate.collection.Map.readFrom(Map.java:200)
at net.sf.hibernate.loader.Loader.readCollectionElement(Loader.java:384)
at net.sf.hibernate.loader.Loader.getRowFromResultSet(Loader.java:240)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:285)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:138)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:1020)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:995)
at net.sf.hibernate.loader.CollectionLoader.initialize(CollectionLoader.java:83)
at net.sf.hibernate.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:288)
at net.sf.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:3315)
at net.sf.hibernate.collection.PersistentCollection.forceInitialization(PersistentCollection.java:336)
at net.sf.hibernate.impl.SessionImpl.initializeNonLazyCollections(SessionImpl.java:3168)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:143)
at net.sf.hibernate.loader.Loader.doList(Loader.java:1063)
at net.sf.hibernate.loader.Loader.list(Loader.java:1054)
at net.sf.hibernate.hql.QueryTranslator.list(QueryTranslator.java:854)
at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1554)
at net.sf.hibernate.impl.QueryImpl.list(QueryImpl.java:49)
at net.sf.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:550)

Try specifying your types explicitly on all properties.

dont I do it already?
If I take the <map...>...</map> then it works, so the problem is obviousely in my collection mapping.

here is the full stack trace:
------------------------------------------------------------------------
net.sf.hibernate.type.SerializationException: could not deserialize
at net.sf.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:197)
at net.sf.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:220)
at net.sf.hibernate.type.SerializableType.fromBytes(SerializableType.java:73)
at net.sf.hibernate.type.SerializableType.get(SerializableType.java:38)
at net.sf.hibernate.type.NullableType.nullSafeGet(NullableType.java:62)
at net.sf.hibernate.type.NullableType.nullSafeGet(NullableType.java:53)
at net.sf.hibernate.collection.AbstractCollectionPersister.readElement(AbstractCollectionPersister.java:363)
at net.sf.hibernate.collection.Map.readFrom(Map.java:200)
at net.sf.hibernate.loader.Loader.readCollectionElement(Loader.java:305)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:219)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:133)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:915)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:890)
at net.sf.hibernate.loader.CollectionLoader.initialize(CollectionLoader.java:83)
at net.sf.hibernate.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:284)
at net.sf.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:3264)
at net.sf.hibernate.collection.PersistentCollection.forceInitialization(PersistentCollection.java:336)
at net.sf.hibernate.impl.SessionImpl.initializeNonLazyCollections(SessionImpl.java:3119)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:138)
at net.sf.hibernate.loader.Loader.doList(Loader.java:958)
at net.sf.hibernate.loader.Loader.list(Loader.java:949)
at net.sf.hibernate.hql.QueryTranslator.list(QueryTranslator.java:846)
at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1543)
at net.sf.hibernate.impl.QueryImpl.list(QueryImpl.java:39)
at dd.SearchService.indexAllProds(SearchService.java:77)
at dd.struts.action.LuceneIndex.execute(LuceneIndex.java:25)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:397)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:697)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.jboss.web.tomcat.security.CustomPrincipalValve.invoke(CustomPrincipalValve.java:44)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:169)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)
Caused by: java.io.StreamCorruptedException: invalid stream header
at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:737)
at java.io.ObjectInputStream.<init>(ObjectInputStream.java:253)
at net.sf.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:189)
... 62 more

What is the java type of the Id property on the proj.Unit class?

that is "java.lang.Long".

If I comment out the <map...>...</map> from "proj.Prod" then it works fine.

Do I need to actually have <many-to-one> from proj.Unit back to proj.Prod as well?

tried the last mentioned, didn't help.

First, for future reference, there is a "code" tag within the editor here that lets you post *formatted* code snippets. Please use it.

The problem is that you define a map whose elements are of type "Unit", which is also a mapped entity. So this is *supposed* to be a one-to-many entity association. But that's not what you have defined. You use the <element/> nested tag within the <map/> which is instead used to define a collection of "simple types". So Hibernate is serializing your Unit instances into the DB.

What you want instead is:


Also, I'm a little lost as to why you'd want to load a map of units that belong to a given product, and key that map by product-id. The map keys will all be the same.

Steve, thanks for the tips about the code. I am going to use it from now on.

Of course I wanted the prod to have its units by their key(unitid) and the Unit object in the map. Anyway, its working now.
Actually, to be honest I have tried one-to-many association before posting it but I got the {1231=null} when I wrote out to System.out the map being populated. The problem is that Unit object overrides toString() which in turn returns a property that is not set and returning null (I thought the units were not inited), meaning it WAS working in the first place.

Sorry guys for causing troubles and thanks for the help.