[Building Sakai] ClassCastException implementing CourseGradesToSpreadsheetConverter

[Bryan Holladay]

This is an issue I see a lot.  It basically comes down to this:

"The class objects were loaded in different classloaders, therefore
the instances created from in each of classes are seen as
'incompatible'. This is a common issue in a an environment where there
are many different classloaders being used and objects are being
passed around. These issues can easily arise in JEE and portal
environments."

-Source: Internet/Google

 just throwing out quick ideas w/o knowing how your code is set up:

Try to implement this in the same layer as the API or don't import
jars, but instead use what's already there or access it from
Edu-services if that's where it's create, ect...


Thanks,
Bryan



On Wed, Aug 17, 2011 at 10:12 AM, Gross,Christopher <ufchrisg at ufl.edu> wrote:
> The jars are there (the converters appear in tomcat/components/).
> Besides, a missing jar would likely give me some problems when tomcat is
> starting up and/or result in a bean failing to initialize.
>
> Thanks!
>
> -Chris
>
> On 8/17/11 4:26 AM, "DAVID ROLDAN MARTINEZ" <darolmar at upvnet.upv.es> wrote:
>
>>I suggest checking if you have all the *.jar you need available.
>>
>>Hope this helps.
>>
>>David
>>________________________________________
>>De: sakai-dev-bounces at collab.sakaiproject.org
>>[sakai-dev-bounces at collab.sakaiproject.org] En nombre de
>>Gross,Christopher [ufchrisg at ufl.edu]
>>Enviado el: martes, 16 de agosto de 2011 22:54
>>Para: sakai-dev at collab.sakaiproject.org
>>Asunto: [Building Sakai] ClassCastException implementing
>>CourseGradesToSpreadsheetConverter
>>
>>Hello!
>>
>>We are attempting to create our own implementation of the
>>CourseGradesToSpreadsheetConverter interface (gradebook service), however
>>we are receiving a ClassCastException when attempting to export course
>>grades from the gradebook tool. To ensure this was not a problem in our
>>code we set gradebook.coursegrades.converter to
>>"org.sakaiproject.gradebooksample.CourseGradesToSpreadsheetConverterSample
>>"
>> in sakai.properties, which is the sample that is included in the
>>gradebook tool's source. The result is that both implementations are
>>causing the same ClassCastException when a user attempts to export the
>>course grades in the gradebook.
>>
>>This setup is using gradebook 2.8.x and edu-services 1.1.x
>>
>>A small snippet of the output is below.
>>
>>I am hoping that someone may see something that I am not or will confirm
>>that this is something that needs to be submitted to the JIRA.
>>
>>Thanks!
>>
>>----
>>
>>2011-08-16 16:28:05.634 [ERROR]
>>org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/sakai-grad
>>e
>>book-tool].[sakai.gradebook.tool]:691 - Servlet.service() for servlet
>>sakai.gradebook.tool threw exception
>>java.lang.ClassCastException:
>>org.sakaiproject.gradebooksample.CourseGradesToSpreadsheetConverterSample
>>cannot be cast to
>>org.sakaiproject.tool.gradebook.CourseGradesToSpreadsheetConverter
>>        at
>>org.sakaiproject.tool.gradebook.ui.CourseGradeDetailsBean.getSpreadsheetDa
>>t
>>a(CourseGradeDetailsBean.java:322)
>>        at
>>org.sakaiproject.tool.gradebook.ui.CourseGradeDetailsBean.exportCsv(Course
>>G
>>radeDetailsBean.java:296)
>>...
>>
>>
>>--
>>
>>Christopher Gross
>>University of Florida
>>
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