1. A data structure comprising: a plurality of simple objects each comprising a content type indicator, a size indicator, and one or more simple data types; and a plurality of complex objects each comprising a content type indicator, a size indicator, and one or more child objects, each of the child objects being one of the plurality of simple objects, one of the plurality of complex objects, a collection of one or more of the plurality of simple objects, or a collection of one or more of the plurality of complex objects; the plurality of complex objects comprising at least one layer object comprising a first child object and a second child object, the first child object being a first collection of one or more of the plurality of complex objects, the second child object being a second collection of one or more of the plurality of complex objects, the first collection storing information for configuring a virtual filesystem of a virtual application at application startup, the second collection storing information for configuring a virtual registry of the virtual application at application startup.