java.lang.ClassCastException: sametype cannot be cast to sametype

Question

very strange exception

my code

 Query q = em.createQuery("SELECT  u FROM Chatuser u");

            List<Chatuser> list = (List<Chatuser>) q.getResultList();
            for (int i = 0; i < list.size(); i++) {
                Object aa = list.get(i);
                Chatuser chatuser = (Chatuser)aa;

exception

   ex = (java.lang.ClassCastException) java.lang.ClassCastException: Entities.service.Chatuser cannot be cast to Entities.service.Chatuser

what is the problem ?

If you did a redeploy try restarting the server. I ran into the same problem in jBoss once when I was redeploying an app. — Thihara, Jun 21 '13 at 09:20

score 1 · Answer 1 · edited May 23 '17 at 12:22

1

This post probably answers also your question
Java, getting class cast exception where both classes are exactly the same

There could be problem with conflicting Classloaders

edited May 23 '17 at 12:22

Community

1
1

answered Jun 21 '13 at 09:37

Ondrej Bozek

10,987
7
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I restarted the pc and it worked "older versions of the class retained in memory causing ClassCastException" – Mohammed Subhi Sheikh Quroush Jun 21 '13 at 10:47

Josef Prochazka · Answer 2 · 2013-06-21T09:39:37.043

0

it is because the generics

List<Chatuser> list =

use this form

for(ChatUser u : list) {
u.doSomething();
}

edited Jun 21 '13 at 09:39

answered Jun 21 '13 at 09:33

Josef Prochazka

1,273
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9
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can you post the stacktrace ? – Josef Prochazka Jun 21 '13 at 10:46

score 0 · Answer 3 · answered Jun 21 '13 at 09:39

please try the following :

Query q = em.createQuery("SELECT  u FROM Chatuser u", Chatuser.class);

List<Chatuser> list = q.getResultList();

for (Chatuser chatuser : list) {
    ....
    chatuser.doSomething();
    ...
}

If you set the target Class on the createQuery Method already, you can avoid the downcast. If its not working, please past more infos, (Chatuser.java) JPA(Hibernate) Version, etc)

Cheers Jens

java.lang.ClassCastException: sametype cannot be cast to sametype

3 Answers3

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