1. A method of garbage collection in a virtualization environment, the virtualization environment comprising a virtual machine hypervisor, at least one guest operating system and at least one application program that runs on the guest operating system, wherein the application program performs memory management using a garbage collection mechanism, the method comprising the steps of: requesting the guest operating system to assign a memory space for the application program in response to an operating environment of the application program initiating garbage collection; marking live objects in an original memory space of the application program in response to the guest operating system assigning the memory space for the application program; replicating the marked live objects to the assigned memory space; and releasing the original memory space of the application program to the guest operating system.