ClassCastException when retrieving AgendaEventListener collection

Following part of Spring configuration:

<bean id="debug-agenda-listener"
class="org.drools.event.DebugAgendaEventListener" />
<drools:ksession id="statefulSession" type="stateful" kbase="kbase1">
<drools:agendaEventListener ref="debug-agenda-listener"/>
</drools:ksession>

when trying to find out AgendaEventListener count registered in knowledge
stateful session, got this exception:

org.springframework.web.util.NestedServletException: Request processing failed;
nested exception is java.lang.ClassCastException:
org.jbpm.process.instance.ProcessRuntimeImpl$3 cannot be cast to
org.drools.event.rule.AgendaEventListener

org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:656)

org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)

root cause

java.lang.ClassCastException: org.jbpm.process.instance.ProcessRuntimeImpl$3
cannot be cast to org.drools.event.rule.AgendaEventListener

org.drools.impl.StatefulKnowledgeSessionImpl.getAgendaEventListeners(StatefulKnowledgeSessionImpl.java:182)

com.redhat.droolsspring.controllers.DroolsIntegrationStatefulTest.testAgendaListener(DroolsIntegrationStatefulTest.java:28)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:616)

org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:174)

org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:421)

org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:409)

org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:771)

org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716)

org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)

org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)

See attachment 542456 [details]:
build as maven project, then deploy to tomcat, open webapp in browser and click
on the first link.