Error invoking event, the class org.ofbiz.learning.learning.LearningEvents

[nimco]

hi
i'm new in ofbiz and i'm followup the book "the beginer toturial" .
i add a java class "LearningEvents.java" in "ofbiz\hot-deploy\learning\src\org\ofbiz\learning\learning"
and define it in the controller

<request-map uri="processFirstForm">
                <event type="java" path="org.ofbiz.learning.learning.LearningEvents" invoke="processFirstForm"/>
                <response name="success" type="view" value="OneFormScreen"/>
</request-map> 

but when trying to invoke the url "http://localhost:8080/learning/control/processFirstForm"
i get
ERROR rendering error page [/error/error.jsp], but here is the error text: org.ofbiz.webapp.event.EventHandlerException: Error invoking event, the class org.ofbiz.learning.learning.LearningEvents was not found

any idea ?