error "Factory method "getBookings" with a void return type must have an associated @Out/Databinder"

eclipse will report an error on problems like this:
Severity and Description Path Resource Location Creation Time Id
Factory method "getBookings" with a void return type must have an associated @Out/Databinder elanceclone/WEB-INF/src/java/org/jboss/seam/example/hibernate BookingListAction.java line 48 1206419587569 2234