1. A method of providing target computing environment control of a resource to be accessed by existing, native program code, the method comprising: transparently replacing an uncontrolled resource within memory space directly accessible by an existing, native program code with a handle within the memory space directly accessible by the existing, native program code, the handle representing a resource controlled by a target computing environment and comprising a token which when accessed redirects an operation of the existing, native program code to the resource controlled by the target computing environment, the uncontrolled resource being uncontrolled by the target computing environment, and the resource controlled by the target computing environment being in memory space which is inaccessible directly by the existing, native program code, the target computing environment comprising a target operating, system which is different from a native operating system of a native computing environment for which the existing, native program code was written; transparently interposing at least one resource management service of the target computing environment between the existing, native program code and the resource controlled by the target computing environment, wherein the at least one resource management service provides target computing environment control over the resource; and wherein the transparently replacing comprises mapping an identifier of the uncontrolled resource in the existing, native program code to the handle representing the resource controlled by the target computing environment, and wherein the target computing environment shares access to the resource controlled by the target computing environment with the existing, native program code through the handle within the memory space directly accessible by the existing, native program code.