Help with: oracle.toplink.essentials.exceptions.ValidationException

Question

hi guys,
I really need ur help with this.
I have a remote session bean that retrieves a list of books from the database using entity class and I call the session bean from a web service. The problem is that when i display the books in a jsp directly from the session bean everything works ok but the problem comes when I call the session bean via the web service than it throws this:
Exception Description: An attempt was made to traverse a relationship using indirection that had a null Session. This often occurs when an entity with an uninstantiated LAZY relationship is serialized and that lazy relationship is traversed after serialization. To avoid this issue, instantiate the LAZY relationship prior to serialization.
at oracle.toplink.essentials.exceptions.ValidationException.instantiatingValueholderWithNullSession(ValidationException.java:887)
at oracle.toplink.essentials.internal.indirection.UnitOfWorkValueHolder.instantiate(UnitOfWorkValueHolder.java:233)
at oracle.toplink.essentials.internal.indirection.DatabaseValueHolder.getValue(DatabaseValueHolder.java:105)
at oracle.toplink.essentials.indirection.IndirectList.buildDelegate(IndirectList.java:208)
at oracle.toplink.essentials.indirection.IndirectList.getDelegate(IndirectList.java:330)
at oracle.toplink.essentials.indirection.IndirectList$1.<init>(IndirectList.java:425)
at oracle.toplink.essentials.indirection.IndirectList.iterator(IndirectList.java:424)
at com.sun.xml.bind.v2.runtime.reflect.Lister$CollectionLister.iterator(Lister.java:278)
at com.sun.xml.bind.v2.runtime.reflect.Lister$CollectionLister.iterator(Lister.java:265)
at com.sun.xml.bind.v2.runtime.property.ArrayElementProperty.serializeListBody(ArrayElementProperty.java:129)
at com.sun.xml.bind.v2.runtime.property.ArrayERProperty.serializeBody(ArrayERProperty.java:152)
at com.sun.xml.bind.v2.runtime.ClassBeanInfoImpl.serializeBody(ClassBeanInfoImpl.java:322)
at com.sun.xml.bind.v2.runtime.XMLSerializer.childAsXsiType(XMLSerializer.java:681)
at com.sun.xml.bind.v2.runtime.property.ArrayElementNodeProperty.serializeItem(ArrayElementNodeProperty.java:65)
at com.sun.xml.bind.v2.runtime.property.ArrayElementProperty.serializeListBody(ArrayElementProperty.java:168)
at com.sun.xml.bind.v2.runtime.property.ArrayERProperty.serializeBody(ArrayERProperty.java:152)
at com.sun.xml.bind.v2.runtime.ClassBeanInfoImpl.serializeBody(ClassBeanInfoImpl.java:322)
at com.sun.xml.bind.v2.runtime.XMLSerializer.childAsXsiType(XMLSerializer.java:681)
at com.sun.xml.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:277)
at com.sun.xml.bind.v2.runtime.BridgeImpl.marshal(BridgeImpl.java:100)
at com.sun.xml.bind.api.Bridge.marshal(Bridge.java:141)
at com.sun.xml.ws.message.jaxb.JAXBMessage.writePayloadTo(JAXBMessage.java:315)
at com.sun.xml.ws.message.AbstractMessageImpl.writeTo(AbstractMessageImpl.java:142)
at com.sun.xml.ws.encoding.StreamSOAPCodec.encode(StreamSOAPCodec.java:108)
at com.sun.xml.ws.encoding.SOAPBindingCodec.encode(SOAPBindingCodec.java:258)
at com.sun.xml.ws.transport.http.HttpAdapter.encodePacket(HttpAdapter.java:320)
at com.sun.xml.ws.transport.http.HttpAdapter.access$100(HttpAdapter.java:93)
at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:454)
at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:244)
at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:135)
at com.sun.enterprise.webservice.JAXWSServlet.doPost(JAXWSServlet.java:176)
... 29 more
This happens when I test the web service using netbeans 6.5.
here's my code:
session bean:
ArrayList bookList = null;
public ArrayList retrieveBooks()
try
List list = em.createNamedQuery("Book.findAll").getResultList();
bookList = new ArrayList(list);
catch (Exception e)
e.getCause();
return bookList;
web service:
@WebMethod(operationName = "retrieveBooks")
public Book[] retrieveBooks()
ArrayList list = ejbUB.retrieveBooks();
int size = list.size();
Book[] bookList = new Book[size];
Iterator it = list.iterator();
int i = 0;
while (it.hasNext())
Book book = (Book) it.next();
bookList[i] = book;
i++;
return bookList;
Please help guys, it's very urgent

Answer 1

Yes i have a relationship but i didnt want it to be directly. Maybe this is a design problem but in my case I dont expect any criminals to be involved in lawsuit. My tables are like that:
CREATE TABLE IF NOT EXISTS Criminal(
     criminal_id INTEGER NOT NULL AUTO_INCREMENT,
     gender varchar(1),
     name varchar(25) NOT NULL,
     last_address varchar(100),
     birth_date date,
     hair_color varchar(10),
     eye_color varchar(10),
     weight INTEGER,
     height INTEGER,
     PRIMARY KEY (criminal_id)
ENGINE=INNODB;
CREATE TABLE IF NOT EXISTS Lawsuit(
     lawsuit_id INTEGER NOT NULL AUTO_INCREMENT,
     courtName varchar(25),
     PRIMARY KEY (lawsuit_id),
     FOREIGN KEY (courtName) REFERENCES Court_of_Law(courtName) ON DELETE NO ACTION
ENGINE=INNODB;
CREATE TABLE IF NOT EXISTS Rstands_trial(
     criminal_id INTEGER,
     lawsuit_id INTEGER,
     PRIMARY KEY (criminal_id, lawsuit_id),
     FOREIGN KEY (criminal_id) REFERENCES Criminal(criminal_id) ON DELETE NO ACTION,
     FOREIGN KEY (lawsuit_id) REFERENCES Lawsuit(lawsuit_id) ON DELETE CASCADE
ENGINE=INNODB;So I couldnt get it.