Avatar billede fredand Forsker
02. januar 2017 - 22:42 Der er 8 kommentarer og
2 løsninger

Problems with hibernate and collections

Hello guys!

We are migrating from:
Jboss 5.0 to Jboss 6.3
java 6 to java 7
ojdbc6_g-11.2.0.2.0.jar to ojdbc7_g-12.1.0.1.jar

In Jboss 6.3 we are getting this error:

Caused by: java.lang.RuntimeException: org.hibernate.exception.GenericJDBCException: could not initialize a collection: [com.company.AClass.bs#23]

I have also tried to use ojdbc6_g-11.2.0.2.0.jar, but we get the same error.
The strange thing is that this worked fine in Jboss 5.0 and I thought that it should work as fine in Jboss 6.3.
Below is some code snippets and the db-tables (with values) that are involved.
Do you guys got any idea what might is wrong?
Best regards
Fredrik


@Entity
@Table(name = "ACLASS")
public class AClass

    @Id
    @Column(name = "ID")
    private String    id;

    @Column(name = "NAME")
    private String    name;
   
    @JoinColumn(name = "FK_ACLASS_ID")
    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    private Set<BClass>    bs;
   
    ...


@Entity
@Table(name = "BCLASS")
public class BClass {

    @Id
    @Column(name = "ID")
    String    id;

    @Column(name = "TYPE")
    Type    type;
   
    ...
   

public enum Type {

    A("a", "A"),
    B("b", "B"),
    C("c", "C"),
    D("d", "D"),
    E("e", "E"),
    F("f", "F");
   
    ...
   

The database tables

ACLASS
(AClass.java)

id VARCHAR2(32)
name VARCHAR2(64)

VALUES
1 name_1
2 name_2
3 name_3
4 name_4
5 name_5
6 name_6
7 name_7
8 name_8
9 name_9
10 name_10
11 name_11
12 name_12
13 name_13
14 name_14
15 name_15
16 name_16
17 name_17
18 name_18
19 name_19
20 name_20
21 name_21
22 name_22
23 name_23
24 name_24
25 name_25

   
BCLASS   
(BClass.java)

id VARCHAR2(32)
type VARCHAR2(1)
fk_aclass_id VARCHAR2(32)

VALUES
23a A 23
23b B 23
23c C 23
23e D 23
1  A 7
2  B 7
3  C 7
4  D 7
6  E 7
7  F 7
5  D 14   
Avatar billede arne_v Ekspert
03. januar 2017 - 01:10 #1
JPA with Hibernate as provider I assume.

How does setBs look like?
Avatar billede fredand Forsker
03. januar 2017 - 08:09 #2
Hello!
Yes the imports are like:

import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;


I never thought about those methods but of course those must be of interest!
How ever they do not look fishy to me:


    public Set<BClass> getBs() {
        return bs;
    }
   
    public void setBs(final Set<BClass> pBs) {
            bs = pBs;
    }
Avatar billede fredand Forsker
03. januar 2017 - 22:09 #3
Hello!

Today I thought that if I put a breakpoint in the setBs and getBs perhaps I would get an idea of what is going on, but unfortunately it did not stop on the breakpoint when I executed it so I guess the problem must be something deeper.

Any ideas of how to investigate this is most welcome.
Best regards
Fredrik
Avatar billede fredand Forsker
03. januar 2017 - 22:13 #4
Just wonder what the AClass.bs#23 refers to. In this case number 23 occurs at some places. Could it be something about row/id 23 in the table ACLASS?
Avatar billede arne_v Ekspert
04. januar 2017 - 02:55 #5
Are there another exception besides org.hibernate.exception.GenericJDBCException ?
Avatar billede arne_v Ekspert
04. januar 2017 - 03:05 #6
I am not a JPA guru, but I wonder about:

@JoinColumn(name = "FK_ACLASS_ID")
@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)

I would have made that as:

@OneToMany(mappedBy = "nameOfFieldInBlassNotDatabaseColumn", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
Avatar billede fredand Forsker
04. januar 2017 - 22:14 #7
Hello!

First thanks for your time Arne!

Second, you might be right with your JPA suggestion, I will try it out of course. But since it worked in our old JBoss I guess it should work in our new JBoss.

Third I tracked down the call that gives the exception and with some extra catch I found a extra exception, as you already suspected!

final Query q = em.createNamedQuery(AClass.QUERY_FIND_ALL);
//@NamedQueries({@NamedQuery(name = "AClass.findAll", query = "SELECT r FROM AClass r")})
try
{
    @SuppressWarnings("unchecked")
    final List<AClass> list = q.getResultList();
    return list.toArray(new AClass[list.size()]);
}
catch(Exception ge)
{
    ge.printStackTrace();
    throw ge;
}


How ever the exception (see blow) looks a bit strange since it looks like hibernate/oracle-driver seems to try to read a int from some place. I'm not sure from where, but I guess it must be from some value of those in the first post above. In the database all these columns are Varchar2 of different length.


Caused by: org.hibernate.exception.GenericJDBCException: could not initialize a collection: [com.company.AClass.bs#23]
  at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54)
  at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:124)
  at org.hibernate.loader.Loader.loadCollection(Loader.java:2269)
  at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:65)
  at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:674)
  at org.hibernate.event.internal.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:
  at org.hibernate.internal.SessionImpl.initializeCollection(SessionImpl.java:1774)
  at org.hibernate.collection.internal.AbstractPersistentCollection.forceInitialization(AbstractPersistentCollection.java:696)
  at org.hibernate.engine.internal.StatefulPersistenceContext.initializeNonLazyCollections(StatefulPersistenceContext.java:1037)
  at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:353)
  at org.hibernate.loader.Loader.doList(Loader.java:2550)
  at org.hibernate.loader.Loader.doList(Loader.java:2536)
  at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2366)
  at org.hibernate.loader.Loader.list(Loader.java:2361)
  at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:495)
  at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:357)
  at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:198)
  at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1194)
  at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101)
  at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:268)
  ... 283 more
Caused by: java.sql.SQLException: Kunde inte konvertera till intern representation
  at oracle.jdbc.driver.CharCommonAccessor.getInt(CharCommonAccessor.java:239)
  at oracle.jdbc.driver.T4CVarcharAccessor.getInt(T4CVarcharAccessor.java:601)
  at oracle.jdbc.driver.GeneratedStatement.getInt(GeneratedStatement.java:630)
  at oracle.jdbc.driver.GeneratedScrollableResultSet.getInt(GeneratedScrollableResultSet.java:1324)
  at oracle.jdbc.driver.GeneratedResultSet.getInt(GeneratedResultSet.java:3796)
  at org.jboss.jca.adapters.jdbc.WrappedResultSet.getInt(WrappedResultSet.java:1073)
  at org.hibernate.type.EnumType$OrdinalEnumValueMapper.getValue(EnumType.java:372)
  at org.hibernate.type.EnumType.nullSafeGet(EnumType.java:107)
  at org.hibernate.type.CustomType.nullSafeGet(CustomType.java:127)
  at org.hibernate.type.AbstractType.hydrate(AbstractType.java:106)
  at org.hibernate.persister.entity.AbstractEntityPersister.hydrate(AbstractEntityPersister.java:2924)
  at org.hibernate.loader.Loader.loadFromResultSet(Loader.java:1695)
  at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1627)
  at org.hibernate.loader.Loader.getRow(Loader.java:1509)
  at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:719)
  at org.hibernate.loader.Loader.processResultSet(Loader.java:949)
  at org.hibernate.loader.Loader.doQuery(Loader.java:917)
  at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:348)
  at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:318)
  at org.hibernate.loader.Loader.loadCollection(Loader.java:2262)
  ... 300 more

Avatar billede arne_v Ekspert
05. januar 2017 - 01:12 #8
The getInt error is indeed puzzling.

I think you should try changing the annotations.
Avatar billede fredand Forsker
05. januar 2017 - 15:53 #9
Hello!

I hope managed to changed the annotation to use the mappedBy, how ever it turned out like this.

In AClass I changed the annoation to

@OneToMany(mappedBy = "aAClass", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
private Set<BClass>    bs;


In BClass it seamed that I had to add a field of ACLass to meet up the requirements for this relation.

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "FK_ACLASS_ID")
AClass aAClass;


(I also added set and get methods for aAClass in BClass.)

But when I run it I get the same error:
   
...SQLException: Kunde inte konvertera till intern representation
at oracle.jdbc.driver.CharCommonAccessor.getInt(CharCommonAccessor.java:239)

Do you see any misstakes in the annotation?
Best regards
Fredrik
Avatar billede fredand Forsker
05. januar 2017 - 20:18 #10
Hello!

I think we found a solution after all Arne. With your help regarding looking for other exceptions I got the idea to google the net for: "CharCommonAccessor.getInt could not initialize a collection"
...which led me to:
http://stackoverflow.com/questions/26889015/every-time-i-think-i-fixed-it-could-not-initialize-a-collection-error-keeps-c
The solution found above turned out to be that I needed to add this annotation to the enumeration Type:


    @Enumerated(EnumType.STRING)
    @Column(name = "TYPE")
    Type    type;
 

After this change it worked fine. Really strange that we did not needed to use this in our former platform.

Tusind tak Arne for this discussion!

Best regards
Fredrik
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