Methods, systems, and computer programs manage memory of a runtime environment executing on a virtual machine. A controller acts as an intermediary layer between the runtime environment and outside clients. The runtime environment coordinates with the controller to “hibernate” during idle periods to more efficiently utilize memory, and to quickly “refresh” state upon receiving an access attempt. A hypervisor may perform memory page compression on one or more guest “physical” memory pages utilized by an idle runtime environment. While hibernating, the runtime environment may use a listener thread to monitor for refresh requests and awaken the runtime environment when needed.