Not able to get json data from a service call

[rshekhar.in]

i have created a service
<service name="service1" engine="simple" location="component://customComponent/services.xml" invoke="service1method">
      <attribute name="attrib1" mode="IN" type="String" optional="false"></attribute>
      <attribute name="attrib2" mode="OUT" type="String" optional="false"></attribute>           
     </service>

the controller is configured for the service like
<request-map uri="service1Ajax">
     <security https="false" auth="false"/>
     <event type="service" invoke="service1" />
     <response name="success" type="request" value="json"/>
        <response name="error" type="request" value="json"/> 
    </request-map>

I have checked that the service service1 is working fine and gives attrib2 as out param.

But i am unable to convert the String to json as response....

When i invoke the url, the error is
org.ofbiz.webapp.control.RequestHandlerException: Unknown chained request [json]; this request does not exist

Please help!