Methods, systems, and computer program products for dynamically modifying an application program's behavior in response to changing environmental conditions (such as network changes, system changes, and so forth). The application may solicit such information, and/or may receive unsolicited environmental change notifications. In response to a change notification, the application may take one or more of the following approaches to adapt to the changing conditions: (1) alter its execution; (2) modify its use of, or control of, other cooperating application; and (3) modify the selection of application execution threads. (An application might also decide to make no changes in its behavior.)