question: gets the callback url . concode_field_sep long serialVersionUID concode_elem_sep Integer hubTopicId concode_elem_sep Integer hubSubscriptionStatusId concode_elem_sep String callbackUrl concode_elem_sep String secret concode_elem_sep Integer leaseSeconds concode_field_sep void setLeaseSeconds concode_elem_sep void setHubTopicId concode_elem_sep Integer getHubSubscriptionStatusId concode_elem_sep void setHubSubscriptionStatusId concode_elem_sep void setCallbackUrl concode_elem_sep String getSecret concode_elem_sep void setSecret concode_elem_sep Integer getLeaseSeconds concode_elem_sep Integer getHubTopicId
target: String function ( ) { return callbackUrl ; }