Hi
We are getting the following exception, when we try to fetch data using Query.list. Some scenario we are getting on instance of PersistentSet , but expected is an implementation of List due to which, getting class cast exception.

Version of Hibernate 3.2. it would be great if some help to resolve this issue.

java.lang.ClassCastException: org.hibernate.collection.PersistentSet cannot be cast to java.util.List
at $Proxy102.getDatalist(Unknown Source)
at com.test.service.impl.MyPageServiceImpl.getMyPods(MyPageServiceImpl.java:185)
at com.test.service.impl.MyPageServiceImpl.getMyPagePodDetails(MyPageServiceImpl.java:79)
at sun.reflect.GeneratedMethodAccessor1122.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:310)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:77)
at com.test.management.CallTracer.trace(CallTracer.java:46)
at sun.reflect.GeneratedMethodAccessor69.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:627)
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:616)
at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:64)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:165)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)

Are you using lazy="extra" on the entities returning PersistentSet , or have some type of ordered bag / List config? For the latter see:

http://docs.jboss.org/hibernate/core/3. ... nt-classes

Here is the code snippet which can explain what we are doing..

Basically the DAO class returns an instance of List most of the cases. But in some cases it is returning an instance of a PersistentSet due to which we are getting a ClassCastException.
Since this is happening only in production and that too for a specific users we are not able to figure out the root cause as it cant be re-producible in our test environments.


Peristent Entity:
--------------------
public class MyEntityImpl implements MyEntity {

private Long id;
private User user;
private Integer displayOrder;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
public Long getId() {
return id;
}

public void setId(Long id) {
this.id = id;
}

@ManyToOne(targetEntity = UserImpl.class, fetch = FetchType.LAZY)
@JoinColumn(name = "users_id", referencedColumnName = "id", nullable = false, updatable = false)
public User getUser() {
return user;
}

public void setUser(User user) {
this.user = user;
}

@Column(name = "display_order")
public Integer getDisplayOrder() {
return displayOrder;
}

public void setDisplayOrder(Integer displayOrder) {
this.displayOrder = displayOrder;
}
}


DAO Class:
--------------
public class MyEntityDAO {
public List<MyEntity> getMyEntities(Long userId)
{
List<MyEntity> list = null;
String queryString = "from MyEntityImpl ms where ms.user.id = ? order by ms.displayOrder";

return (List) execute(new HibernateCallback() {
public Object doInHibernate(Session session)
throws HibernateException {
Query queryObject = session.createQuery(queryString);
queryObject.setParameter(0, userId);
return queryObject.list();
}

}
}
}

TEST Class:
----------------
public class MyEntityTest {

public void testMyEntitiesDAO {

MyEntityDAO dao = new MyEntityDAO();

List myEntitties = dao.getMyEntities(new Long(9999));
}
}

Hi,

that's likely a bug, and you're using a stone-aged version.. time to try an update?
All issues are tracked here