Mounting dynamic resources , wicket 1.5

Hi All,

I am trying out the Mounting dynamic resources as explained in the
following article.

http://wicketinaction.com/2011/07/wicket-1-5-mounting-resources/

in the App.java , I have the following.
mountResource("/images/${imgName}", new ImageResourceReference());

The image resource class is exactly the same.

I can see that a nice URL is getting generated. But getting the following
exception on the page and the URL not working.

WARN WicketObjects : Could not resolve class [undefined]
java.lang.ClassNotFoundException: undefined
at
org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1509)
at
org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1359)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at
org.apache.wicket.application.AbstractClassResolver.resolveClass(AbstractClassResolver.java:107)
at
org.apache.wicket.util.lang.WicketObjects.resolveClass(WicketObjects.java:71)
at
org.apache.wicket.request.mapper.AbstractComponentMapper.getPageClass(AbstractComponentMapper.java:138)
at
org.apache.wicket.request.mapper.BookmarkableMapper.parseRequest(BookmarkableMapper.java:110)
at
org.apache.wicket.request.mapper.AbstractBookmarkableMapper.mapRequest(AbstractBookmarkableMapper.java:269)
at
org.apache.wicket.request.mapper.CompoundRequestMapper.mapRequest(CompoundRequestMapper.java:141)
at
org.apache.wicket.request.cycle.RequestCycle.resolveRequestHandler(RequestCycle.java:184)
at
org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:209)
at
org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:283)
at
org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:188)
at
org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:244)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at
org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at
org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at
com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
at
com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at
com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
at
com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
at
com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at
com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at
com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at
com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at
com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at
com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at
com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at
com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:662)