Isolating user interface design from business object design using Java interface concepts

A method of developing a computer software system comprising defining a first interface between a proposed view sub-system and a proposed business logic sub-system, defining a second interface between a proposed handler sub-system and the proposed business logic sub-system, creating the view sub-system in accord with the second interface, and creating the handler sub-system in accord with the second interface. In another form, the invention provides is a related computer software system and computer program.