Creating an API connector to pull web data

Using Bonitasoft 7 community edition. Using Yahoo yql, to get a Yahoo finance API.

I have created API calls in forms to get data from Yahoo.However I need to create a call for the same information within the process.

This seemed like viable option however I have been unable to get it to integrate with Bonita 7 http://community.bonitasoft.com/project/rest-connector

I have been getting the error,

java.lang.reflect.InvocationTargetException com.thoughtworks.xstream.converters.ConversionException: org.bonitasoft.connectors.rest.RESTResult : org.bonitasoft.connectors.rest.RESTResult ---- Debugging information ---- message : org.bonitasoft.connectors.rest.RESTResult cause-exception : com.thoughtworks.xstream.mapper.CannotResolveClassException cause-message : org.bonitasoft.connectors.rest.RESTResult class : java.util.HashMap required-type : java.util.HashMap converter-type : com.thoughtworks.xstream.converters.collections.MapConverter path : /map/entry/org.bonitasoft.connectors.rest.RESTResult line number : 5

version : null

com.thoughtworks.xstream.mapper.CannotResolveClassException: org.bonitasoft.connectors.rest.RESTResult

Does anyone have a recommendation for making an this kind of connector? Or another kind of call for information?