I have a relationship which is somethign similar to the model mentioned below:
public class Parent {
private Long parentId;
private List<Child> children;

@OneToMany(mappedBy = "parent", cascade = CascadeType.ALL)
@OrderBy("childNumber asc")
public List<Child> getChildren() {
return children;
}

@Id
@SequenceGenerator(name = "SOME_ID_GENERATOR", sequenceName = "SOME_ID_SEQ")
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SOME_ID_GENERATOR")
@Column(name = PARENT_ID, nullable = false)
public Long getParentId() {
return parentId;
}
}

public class Child {
private Long childId;
private Parent parent;
private long childNumber;

@Id
@SequenceGenerator(name = "SOME_GENERATOR", sequenceName = "SOME_SEQ")
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SOME_GENERATOR")
@Column(name = "CHILD_ID")
public Long getChildId() {
return childId;
}
public void setChildId(Long childId) {
this.childId = childId;
}

@ManyToOne
@JoinColumn(name = "PARENT_ID")
public Parent getParent() {
return parent;
}
public void setParent(Parent parent) {
this.parent = parent;
}

@Column(name = "CHILD_NUMBER", nullable = false)
public long getChildNumber() {
return childNumber;
}
public void setChildNumber(long childNumber) {
this.childNumber = childNumber;
}
}

Now as you can see the child id is a Long in the Hibernate model. But due to a human error the Oracle database datatype for that field was set to a varchar. The DBA noticed this problem and then decided to change the schema and make it a number instead of a varchar. When this was done all our requests immediately started failing with this exception:

org.hibernate.exception.GenericJDBCException: could not initialize a collection: [Parent.children#56065]
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:140)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:128)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.loader.Loader.loadCollection(Loader.java:2173)
at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:62)
at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:627)
at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:83)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1863)
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:369)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:111)
at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:134)
at org.hibernate.collection.PersistentBag.size(PersistentBag.java:248)
application stack trace
at org.springframework.internal.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:689)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:622)
application stack trace
Caused by: java.sql.SQLException: Fail to convert to internal representation
at oracle.jdbc.driver.CharCommonAccessor.getLong(CharCommonAccessor.java:297)
at oracle.jdbc.driver.T4CVarcharAccessor.getLong(T4CVarcharAccessor.java:862)
at oracle.jdbc.driver.OracleResultSetImpl.getLong(OracleResultSetImpl.java:985)
at oracle.jdbc.driver.OracleResultSet.getLong(OracleResultSet.java:440)
at com.mchange.v2.c3p0.impl.NewProxyResultSet.getLong(NewProxyResultSet.java:2625)
at org.hibernate.type.descriptor.sql.BigIntTypeDescriptor$2.doExtract(BigIntTypeDescriptor.java:61)
at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:64)
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:254)
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:250)
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:230)
at org.hibernate.type.AbstractStandardBasicType.hydrate(AbstractStandardBasicType.java:331)
at org.hibernate.loader.Loader.extractKeysFromResultSet(Loader.java:668)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:606)
at org.hibernate.loader.Loader.doQuery(Loader.java:829)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:274)
at org.hibernate.loader.Loader.loadCollection(Loader.java:2166)
at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:62)
at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:627)
at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:83)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1863)
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:369)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:111)
at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:134)
at org.hibernate.collection.PersistentBag.size(PersistentBag.java:248)


Since the hibernate datatype was long we are wondering why hibernate threw this exception when the data type was changed to number. The DBA immediately reverted it back and then it went away. Does anyone have any similar experience? Or does someone know if hibernate caches the table schema somewhere and that caused a problem?

Any help would be appreciated.

Thanks.