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 run-time code for an application, the run-time code being generated from a converted design-time representation of the application, wherein: the converted design-time representation of the application is generated from an original design-time representation of the application developed for use in a first run-time environment for executing applications having been developed in a first design-time environment, the first design-time environment using a first programming model comprising one or more first model elements including screens and processing logic for each screen, the original design-time representation including one or more application screens and original processing logic for each application screen, the original processing logic including a call to a run-time module in the first run-time environment; and the converted design-time representation of the application is for use in a second run-time environment for executing applications having been developed in a second design-time environment, the second design-time environment using a second programming model comprising one or more second model elements including models, views, and controllers, the converted design-time representation including one or more application views based on the one or more application screens, and converted processing logic based on the original processing logic, the converted processing logic being capable of being executed in the second run-time environment; and executing the run-time code in the second run-time environment using an adapter operable to interface with the run-time module in the first run-time environment.