Grails error only on Tomcat server; not reproducible locally: Error executing tag <g:link>: object is not an instance of declaring class

Question

I've got a weird bug on the live server. It happens only on a specific action (a search). I can't reproduce it locally (where I run the code using grails run-app ), and I can't reproduce it on the test server, which runs Tomcat in exactly the same way as the production server. I've copied the production database to local, and I still can't reproduce the error. The only config differenes are that mail is enabled and some other minor stuff, none of which seems relevant here.

I have no idea where to look, because I have no idea what "object is not an instance of declaring class" means. Or more importantly, why this would only be a problem on the production server. Here's the full error:

Error 500: Error processing GroovyPageView: Error executing tag <g:link>: object is not an instance of declaring class at /WEB-INF/grails-app/views/dealer/list.gsp:41
Servlet: grails
URI: /grails/dealer/list.dispatch
Exception Message: object is not an instance of declaring class
Caused by: Error processing GroovyPageView: Error executing tag <g:link>: object is not an instance of declaring class at /WEB-INF/grails-app/views/dealer/list.gsp:41
Class: gsp_quotations_dealerlist_gsp
At Line: [72] 

The .gsp code around line 41 is:

<g:each in="${dealerInstanceList}" status="i" var="dealerInstance">
<tr class="${(i % 2) == 0 ? 'odd' : 'even'}">
  <td><g:link action="show" id="${dealerInstance.id}">${fieldValue(bean:dealerInstance, field:'name')}</g:link></td>
  <td><g:link action="show" id="${dealerInstance.id}">${fieldValue(bean:dealerInstance, field:'address')}</g:link></td>
  <td><g:link controller="quoteSettings" action="adminEdit" id="${dealerInstance.id}">${dealerInstance?.quoteSettings?.pricingTables?.size() > 0}</g:link></td>
</tr>
</g:each>

Line 41 is the last g:link tag.

Note again that all of this works fine locally and on the test server. I'm completely stumped.

Answer 1

The error " object is not an instance of declaring class " is usually associated with environment issues. Check your JVM and tomcat versions in server.

Try using same JVM version for production and development.

Answer 2

How does you UrlMapping.groovy look like? did you modify it? also, try using <g:createLink ...> tag instead of <g:link> and play with the "absolute" param: http://grails.org/doc/1.0.x/ref/Tags/createLink.html