1. A method executed by a processor for class isolation to minimize memory usage, comprising: receiving a request for a requested class object from an application running on a device; retrieving a class instance for the requested class object from a memory; determining if the class instance for the requested class object corresponds to an isolated system class; determining if the class instance for the requested class object corresponds to an application class in response to the class instance not corresponding to the isolated system class; determining that the class instance for the requested class object corresponds to a shared system class in response to the class instance not corresponding to the application class and the isolated system class; and obtaining a proxy class object for the shared system class in response to the class instance for the requested class object corresponding to the shared system class.