[undertow-dev] ClassCastException when retrieving a beans from CDI with Weld Proxy beans

[Martin Kouba]

Hi Eric,

feel free to ask on Weld ML, irc, gitter or forums - 
http://weld.cdi-spec.org/community

And if possible provide a simple test app/reproducer.

Martin

Dne 18.4.2017 v 00:01 Stuart Douglas napsal(a):
> It sounds like a class loading problem. You likely have two copies of
> ejbs.LoginManager, and somehow you are using the wrong one. If you
> look at the output of
> System.out.println(LoginManager.class.getClassLoader()) and
> System.out.println(CDI.current().select(clazz).get().getClass().getClassLoader())
> it should give you a clue.
>
> This is not an Undertow issue.
>
> Stuart
>
> On Fri, Apr 14, 2017 at 11:52 AM, Eric B <ebenzacar at gmail.com> wrote:
>> I posted this problem on StackOverflow, but after doing more research, I'm
>> not sure if this is a Weld, JBoss/WildFly or undertow issue.  Or whether its
>> a framework issue, or how the framework is being used.  If this is not the
>> correct list, can you please let me know which list/group I should be
>> directing the issue to?
>>
>> I'm running into a strange problem and error message that I do not
>> understand. I'm running my application on JBoss 7 EAP.
>>
>> Caused by: java.lang.ClassCastException: Cannot cast
>> ejbs.LoginManager$417755913$Proxy$_$$_Weld$EnterpriseProxy$ to
>> ejbs.LoginManager
>>
>> I'm trying to programatically retrieve an EJB from the CDI context by using
>> its interface and am getting this error message. I've created a sample
>> proof-of-concept that is trying to retrieve EJB beans from the CDI context
>>
>> public <T> T getSesionBean(Class<T> clazz, String name) {
>>     Properties properties = new Properties();
>>
>>     try {
>>         InitialContext initContext = new InitialContext();
>>
>>         return clazz.cast(CDI.current().select(clazz).get());
>>     } catch (Exception e) {
>>         // TODO Auto-generated catch block
>>         throw new RuntimeException(e);
>>     }
>> }
>>
>> It is being called as:
>>
>> LoginManager login = getSesionBean(LoginManager.class);
>>
>> with my EJB defined as:
>>
>> @Stateless(name="LoginManager")
>> @Local(LoginManager.class)
>> @LocalBinding(jndiBinding="LoginManager")
>> public class LoginManagerBean implements LoginManager {
>> ...
>> ...
>> ...
>> }
>>
>> I don't understand it. I'm expecting the bean being retrieved from the
>> context to be a proxy. Shouldn't it be castable to my interface? Otherwise,
>> how am I supposed to retrieve it?
>>
>> More interestingly, this does not seem to be a consistent error; sometimes
>> the code works fine. Sometimes it fails. I haven't been able to determine
>> what makes it work or throw an exception.
>>
>> I found a related issue here, but not sure if this is the same problem
>> and/or which version of Weld is used in JB7EAP. I'm including the following
>> dependency in my application:
>>
>>     <dependency>
>>         <groupId>org.wildfly</groupId>
>>         <artifactId>wildfly-ejb-client-bom</artifactId>
>>         <version>10.1.0.Final</version>
>>         <type>pom</type>
>>     </dependency>
>>
>> Am I doing something completely wrong? If this is a Weld bug, can I use a
>> different proxy system than Weld?  Is this even configurable in undertow?
>>
>>
>> Thanks,
>>
>>
>> Eric
>>
>>
>> _______________________________________________
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>> undertow-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/undertow-dev
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-- 
Martin Kouba
Senior Software Engineer
Red Hat, Czech Republic