1. A method comprising: receiving, by a processing device, a first request to generate an application from source code, wherein the source code comprises a class, and wherein the first request specifies a first value; generating by the processing device, in response to the first request, a first instance of the application, wherein in view of the first value, the class is implemented in the first instance as a singleton and at most one object of the class exists in the first instance at any time; receiving, by the processing device, a second request to generate the application from the source code, wherein the second request specifies a second value that is different than the first value; and generating by the processing device, in response to the second request, a second instance of the application, wherein in view of the second value, the class is implemented in the second instance as a non-singleton.