what is the difference between Home & Component business methods?. can we use ejb-ql in HOME business methods? How EJBHOME business methods differ from home FIND methods? does bean provider has to write the logic for ejbHome method in bean class?
Home methods are used to implement business logic that is not related to a specific entity bean. You can't use EJB-QL for Home methods. You could implement a ejbSelect method on your bean though and call this method from within a Home method.
An ejbSelect method is not required to return references to entities, it may also return the values of a specific (CMP) field for entities satisfying certain criteria.
A Find method is used to obtain (a collection of) *references* to specific entities satisfying certain criteria, which you provide by means of EJB-QL.