1. A computer program product, tangibly embodied in an information carrier, the computer program product being operable to cause data processing apparatus to perform operations comprising: receiving input characterizing an application definition at designtime, the application definition comprising a designtime entity and a configuration of properties of the designtime entity; determining whether the designtime entity is to be compiled by a first generator or a second generator, the first generator supporting compilation of multiple types of designtime entities and the second generator supporting compilation of a specific type of designtime entity; and generating a runtime version of the designtime entity, the runtime version generated with the second generator if the second generator is to be used or, otherwise, generated with the first generator.